Return your current antenna for a refund, if you can.
Given your constraints, go to Walmart and get one of these:
http://www.walmart.com/ip/GE-Amplified-Antenna/20976616 That's as good as you're going to get for $30 with fairly decent VHF performance. If your budget permits spending $125, get one of these (
http://www.walmart.com/ip/Clearstream-2V-J3/24849758), one of these (
http://www.walmart.com/ip/RCA-Digita...ingMethod=p13n) if you can find it in-store, and some RG6or RG59 coax and give it a shot.
Place it in front of a window that faces Cedar Hill and make sure it's oriented so it's horizontal for you initial tests. Perform your channel scan and see how it works out.