The large antenna looks like an older VHF-high/VHF-low combination antenna, which may or may not have UHF capability (looks like perhaps it doesn't). The smaller yagi may be a UHF antenna or some other specialty antenna not for tv. Oftentimes, older antennas that have been not exposed to outside weather can perform just fine in their current place for today's tv reception. 35 miles is usually a receivable distance for attic antennas, so you don't necessarily have to use an outside antenna (at least not yet, until you test things a bit with your current antennas). Some things you might consider:
1 - Is the siding on the outside of your garage (above the garage door) aluminum siding? If so, "aiming through" that siding may be reducing signals significantly and/or causing multipath distortion.
2 - Is your garage door made of metal? If so, raising it (so that it is oriented horizontally directly below your antennas) might be producing a metal ground plane which is slightly enhancing received signals.
3 - The large antenna looks like some of its elements are not lined up straight/properly/squarely to each other, which might decrease the gain of the antenna. Gently bending the elements back in line might help things.
4 - The small yagi antenna (if it is indeed a UHF antenna) looks to be too close to the larger antenna. I would prefer to see it above the large VHF antenna by 2 feet (as high as possible), so that the larger VHF antenna does not "block" signals from reaching that smaller UHF antenna. You could perhaps loosen the clamps holding the mast going through the rotor and raise the mast until it just clears the bottom of the rotor, maybe raising it by a foot or a bit more (which would likely require you to also move the large VHF antenna down that mast by a foot or more). Then, you could remove the small UHF yagi from its current position and clamp it at the very top of the mast.
5 - What kind of coaxial or other cable are you using to connect to the antenna? If it is old 300-ohm flat twinlead or old RG-59 coax, an upgrade to RG-6 would probably help. Also, you would want the coax to run to the tv with the shortest amount of length possible, to preserve maximum signal. Maybe the previous owners had 100 feet of coax running all over the place that could be shortened a lot.
6 - How is the coaxial or other cable connected to the antenna? You'd want to make sure it is attached properly. Maybe there is a 300-to-75-ohm balun connector at the antenna that has gone bad, and that's the only problem.
7 - Which antenna is currently connected to your tv? If it's the small yagi, that would explain the lack of channel 6 reception (it's not designed for VHF-low reception). In order to attach both antennas to your tv, you would join the two antennas together into a single coax dowlead using two short coax lengths (maybe 3-4 feet each) fed into a special, but inexpensive, VHF-UHF combiner called a UVSJ (do not try to use a simple splitter in reverse, as it is not band-separated for this purpose): http://www.solidsignal.com/pview.asp?p=UVSJ
8 - Is the antenna aimed properly toward your stations of interest?
9 - Also, you'd want to make sure that none of the metal crossover lines (connecting the individual elements of your large antenna, and running parallel to the antenna boom) have gotten bent so that they are touching each other, as that would basically short out the antenna.
It's entirely possible that you just have a few problems with one or more of these items, and that, once corrected (perhaps not at significant cost), you will enjoy great reception with the antennas you have. Does the rotor work as well? If so (and assuming that the large antenna clears the rafters while rotating), you might receive additional stations from other directions as well. If you have questions about any of these items, post a few close-up photos of things like the kind of coax you're using and the connection point at the antenna, and maybe we can help out some more.
Hope this is helpful - good luck...