Hi -
Couple of things you should be aware of. Effectiveness of an attic installation is difficult to predict. There are too many unknowns, in the material of the roof and structure, trees and buildings and other obstructions on the other side of the roof, and conductive and/or noisy wires, pipes, chimneys, etc. that are part of the building. Antennas are designed to function in free air, and you can change their electrical characteristics by placing them in other environments. Some building materials are more transparent to signals than others. Stucco, for example, contains wire mesh typically and is basically opaque to TV signals.
So did your little antenna work the same or better in the attic location? Certainly I would test that before proceeding. Just buy a long cable and run it from your TV into the attic space where you want to site the antenna. Hopefully things will improve or at least not get any worse. I'd next get say an RCA ANT751.
http://www.amazon.com/RCA-ANT751-Dur.../dp/B0024R4B5C - which should be available from Walmart - and give it a try in the attic. You have several stations that are quite strong in the 261 to 221 compass direction. It's important that you be able to site thantenna pointing in that direction, unobstructed by chimneys, pipes, wires, etc. Also, if there are trees outside the building that are bare, and you are aiming through them, your reception could get a lot worse in the spring.
If you want, you can go bigger than the ANT751 - but I would try that first and see how it goes. Once you get one TV working to your satisfaction, connected directly to the antenna, you can add splitters and a distribution amp (if needed) to divide the antenna signal.