Before buying a $40 - $60 antenna, why not try an $8 one.
http://www.amazon.com/August-DTA206-...rds=tv+antenna
My sister-in-law bought this one. She is about the same distance from towers as you (17 miles) and she gets every channel she wants. It may struggle with the towers that are 25 - 30 miles but there is only one way to find out.
If it doesn't cut it, your only out $8.
Or, if you need/want a cool little project...
http://www.htpc-diy.com/2012/04/diy-...ndow-hdtv.html
John