Common sense tells me that the idea wouldn`t hold up in a court of law, but if I were you I`d conduct a little bit of Internet research and see if there are any precedents regarding it. While I was at it, I would research what the requirements are for being granted a patent and see if I couldn`t file for a patent myself, without utilizing a lawyer.
One final idea: many lawyers offer a free initial consultation. If you haven`t already consulted an attorney, why not take advantage of that offer with a patent attorney and see what you can find out about the patent application process? Maybe your particular situation is less complex - and therefore - cheaper - than you think. Or maybe there are many tasks that an attorney would normally perform for you that you could perform yourself, minimizing your use of an attorney.
Hope these ideas help. Good luck!
Go to the home page, way down int he left column click on inventing, then click on getting a patent I think it is, then click on the legalzoom.com ad (for a provisional patent) that comes up and read the condensed version of the rules for obtaining a patent. It takes a while to read through all the pages but I did this the other night and it is MUCH easier than trying to find and understand all the info on USPTO`s site.
I am going through the same thing right now and need info on getting a patent and am considering a provisional patent but have more questions to ask yet.
One thing I learned is that if a product has been advertised for sale by you or anyone else, it is then considered "published" and non-patentable, by you or anyone else. Sorry if this info has been repeated in the past, I am new to this site and enjoying it so far.