Here's my opinion: while getting someone to produce your mixes may satisfy your short-term goals of getting a mix onto the site (if i am guessing your goals correctly), learning how to both write and produce will help you out more in the long run. Doing the seperate writing and production thing may work ok now, but I think that it will stifle your creativity and what you will learn and be able to create. For example, if you plan on learning how to score for computer instruments, you're going to have to learn the nuances of your tools rather than have someone try and follow just your midi notes and ship it back to you.
I guess I could elaborate more if you need me too, but my main point is this: I think it'll help you grow more as an artist to learn how to both write and produce, and growing as artists is what we're all after here. So, let's all play nice together and try to help each other out.
Sweet. If you have any questions, post em in here and I'll try to answer.