That fit calc that Mr. McNasty linked to is GREAT! I used it when purchasing my first bike (mail-order) and that bike fits me like a glove!

IMO, a bike fitting at a shop would just be throwing money down the terlit. They'll tell you wahat you already know (or can find out for free on that calc), and may even try and sell you stuff to try and get your bike to work somewhat better.

As others have said, if you can post a pic here of yourself on the bike (preferably with pedal positioned as described above) it would help greatly.