What I did a couple years ago was to purchase this antenna:
http://www.radioshack.com/product/in...ductId=2103088
I put that up on my chimney. I have 4 digital tv station signals here that I pick up over the air. According to antennaweb.org, they range from 257 degrees to 297 degrees. The furthest is 19.0 miles away and I pick it up with an upper 90s percent reception. Sounds similar to your situation. Although I don't know if you have any obstacles. I pretty much don't have any obstructions between my house and the stations.