A lot has already been said about this situation.
A suggestion - if you are really interested in the client's position,
approach the client and determine if you are a viable candidate, and be
honest with the client and ask if they would be willing to approach your
agent to see if a finder's fee can be arranged to terminate your contract
with your agent. It is always best to have your agent and the client work
out the details and arrangment - stay as neutral as possible - you have a
lot to lose and win at the same time depending on the outcome and the
manner in which it is achieved.
Most often such an arrangement can be made and agreeable to all parties
However, I would NOT try to break a contract by means of a lawsuit - 99% of
the time, the only ones who win in such cases are the LAWYERS.
The consulting/contractor market is NOT that big and your reputation is
your biggest asset. Should you sue or bring legal action, you have marked
yourself as an UNTOUCHABLE contractor for future prospects.
Just my 2 cents.