The .com doesn't matter. You don't have to trademark the .com portion of the name. It is like was said, if you grab Ford.com, Ford can take it away from you because Ford is trademarked. If your company name is trademarked, it can not be used in any way shape or form without your permission. Tacking on a .com doesn't work.
Anyway, you need a lawyer, and I always advocate
PrePaid Legal because as a small business owner myself, they have saved me thousands of dollars and lots of headaches for very little money.