Ok, I didn't respond when I first read this because I had no idea what to say.
Now, first, let me see if I get you right -
As I understand it, you have created a set of game mechanincs (somehow Risk-inspired) that your friends/playtesters feel is good enough to be publishable, but you had no specific fictional universe to set it in. At some point you realized that your magic system was (in name at least) approaching copying Erfworld.
And it seems your desired "best case scenario" is to acquire an Erfworld liscence from Rob and Jamie and sell your game in bookstores everywhere and make lots and lots of money.
Assuming this is the situation, you have the following choices:
1) Finish your game, set it in Erfworld, and play with your friends/post the rules here.
Pros: Having fun, larger and more directed playtesting base, Jamie & Rob might look at it, even play it themselves. Sense of satisfaction.
Cons: You can make no money off the game whatsoever, not even to cover costs, as you do not have the rights or liscence to Erfworld characters. Any new Erf characters/fiction based off your game and posted on the internet are open to use by Rob and Jamie, free of charge. The game, in some sense, ceases to be yours and becomes more of a community tool.
Best Case Scenario: The game is a runaway hit on the forums, and eventually (after they publish book 2, maybe book 3, and the world is popular) Rob and Jamie approach you about publishing the game and you work out a mutually agreeable contract. You eventually make a little money and maybe become a "famous" game designer.
Worst Case Scentarios: The game is panned, or someone steals your game mechanics for something else, or you make money off the game and Rob and Jamie are forced to sue you and win your rules as compensation, or someone else makes a deal and creates an official Erf game, and yours is forgotten.
2) Seek out an agreement with Rob and Jamie before finishing the game.
Pros: Don't go into this full of questions and possibilities. Potentially have input from Rob and Jamie.
Cons: You have no bargaining position in negotiating an agreement, and it's probably never gonna happen anyway.
Best Case Scenario: You wow Rob and Jamie, they agree to give you the rights for 2 years, give you all the secret Erf rules (and an NDA), you finish the game and you publish when Book 2 comes out.
Worst Case Scenario: Rob and Jamie try as politely as possible to shoo you in the direction of the man in the white lab coats, and keep an eye on any product you make for similarities to Erfworld.
3) Write your own story
Pros: If your rules are good, and you want to "make a pretty penny" without investing thousands of dollars on a liscence or giving up a large percentage of your grosses, this is the way to go. Release a product entirely of your own design and you get all the money; even if you self-publish a handful of copies, it provides you a legal defense against copycats.
Cons: Your story might suck, and even if it doesn't, you probably won't make much money.
Best Case Scenario: After a few quiet months of self-release, Wil Wheaton blogs about your game, and suddenly you're selling PDFs like gangbusters and a publishing company approaches you about distribution.
Worst Case Scenario: No one plays your game, ever.
4) Hire a writer
Pros: You can get someone to make up an exciting world for your game, probably for free (until you start selling copies, anyway). You only have to split your earnings with one person.
Cons: It's like doing it all yourself, but you don't get all the money.
Best Case Scenario: You're the perfect team, the game finds a distributor or a huge internet following; you make copycat games on peoples' liscences and make a living touring conventions; your partner writes a series of novels based on your game and you both make (relatively) mad money.
Worst Case Scenario: No one plays your game, ever, AND you fight with your writer, during the process, and again after you split up and both do your own thing that is too similar to the other's work.
5) Shop for liscences
Pros: A liscence can get you, a nobody, a chance at publishing a game that will actually get purchased by fans.
Cons: Getting someone to agree, especially if you don't have money to buy a liscence outright, added pressure to succeed, irate fanboys.
Best Case Scenario: Someone decides to give you a shot, gives you the liscence free in return for later profits, you release and are at least as successful as the Serenity or Buffy RPGs.
Worst Case Scenario: Some rich Hollywood types laugh at you, and you never make a game.
6) Release the rules without a story
Pros: You've been working on the mechanics and not the story, so you're much closer to done. No need to deal with anyone else or share profits. If the mechanics are that good, they could stand on their own and lead to future products. You could gain notoriety more easily if the game is not wrapped in someone else's work. Easier to protect against copycats.
Cons: Harder to sell.
Best Case Scenario: The rules are an instant hit. You get distribution for the basic rules, then release supplements GURPS style, plus get liscenses from hot properties and hire writers to do most of the conversion work.
Worst Case Scenario: No one plays your game, ever. Someone steals the rules and releases a game with them.
I am a: Chaotic Neutral Human Bard/Sorcerer (2nd/1st Level)
Str- 12, Dex- 15, Con- 12, Int- 14, Wis- 11, Cha- 13