I would suggest you get some qualified legal advise. A contract is a fairly concise thing that can work both for you and against you. I do not feel too confidant giving out advice on a contract without knowing the in's and out's of the subject matter.
You NEED to contact a lawyer. They, or their paralegal, can write up a contract which will be legal and valid. Procuring a contract from anything other than a lawyer, someone who can practice law in accordance with your state bar, can make the contract invalid depending on circumstances.
Not only that, but without getting a contract specific to your needs and current situation, you could end up screwing yourself over.
I understand that legal consultations can run well into the hundreds of dollars per hour, but you will save yourself that money and more by doing it and not getting a pre-fabbed non specific contract.