You can't fool Mother Nature or violate the laws of physics. Unfortunately, too much of the descriptive literature about antennas is nonsense bordering on the criminally dishonest. The Antennas Direct ClearStream2 you mentioned is only rated at 50 miles and is UHF only. You could easily build a better UHF antenna yourself and save a bunch of $$.
A separate Channel 13 Yagi for the top end of VHF and an 8 bow tie UHF antenna should do the trick -- if they were roof top mounted. I forget the exact rule of thumb but an attic installation is only about 50% as good as a roof top, but usually still better than down in the house itself. At 65 miles distant you should have enough signal strength for an attic installation.
Keep in mind that there are "sweet spots" for reception and their distances apart vary by wavelength. As I recall, a sweet spot for channel 13 is about 12 feet apart from spot to spot, and the distances are proportionally less for the UHF channels. It's all based on wavelengths. But, moving an antenna a few feet one way or another can often make a huge difference, especially for in-attic installations.
I would be tempted to give a channel 13 Yagi a trial in your attic and move it around to try and find its sweet spot. This is the antenna I am using for channel 13:http://www.solidsignal.com/prod_disp...om=Large#xview
The UHF channels might be received OK with an in-attic installation and building one is not too difficult as UHF wavelengths are much shorter than channel 13. Recipes abound here to do so. But, if you build one of the projects listed here make it a large antenna, an 8 bow-tie version. And, again, try moving it left and right and forward and backward to find the "sweet spot" for at least the weakest UHF channel. Unfortunately, sweet spot locations vary by wavelength so the preferred location for one channel may not be the same one as for a different channel. But, Sycamore is only 65 miles away so you should have enough signal strength to allow for a little imprecision in positioning an antenna, especially for UHF.
Again, there is no magic in antenna design. You can't substitute fancy product descriptions for number of working elements and square inches of receiving elements.