Don't worry about the frame size.

You can make a small frame bigger with the right components, but you can't make a big frame smaller.

I like a bike set up a little heavy on the rear wheel and a little lighter on the front, and so I use a setback seatpost to give myself enough room in the cockpit.

I ride with an FSA SL-220 setback seatpost.

They don't cost very much, but you will have a little difficulty finding one.

Consider it worth the search.

Don't confuse this seatpost with the super duper light seatpost FSA makes that has the same design but lighter materials (and costs a fortune).

You can look at this seatpost at the following link, but I don't know if you can buy it there:

http://www.bikeparts.com/productinfo...827-78344.html