Here's The Update:
The installers came this morning, and wouldn't you know it was the same guys that were the ones to install DISH for me in the first place? They thought they were coming to fix a problem and had no instructions from DISH. I explained to them what I did and what DISH told me and they got on the phone and talked for awhile and went to hooking up the antenna. (Side note: I found the combiner that Voom installed, they left it attached to the dish, so I'm glad I didn't use the Installer company's name).
Basically they ended up using two simple diplexors for the whole setup outside and one inside right before the reciever. I don't get exactly the same reception I was when I had Voom, but it's really close. I notice they moved the antenna quite a bit in a different direction...so maybe that's it, I'll move it later tonight maybe.
One of the installers explained that normally they charged extra for doing stuff like that because DISH doesn't pay him for the extra parts, and that they only gave him 20 bucks to come all the way to my house which is an hour away from the company. But he didn't charge me, and it's working, so I'm happy.
I'm wondering now how to hook up a preamp and where to get one, what they cost, if it will actually help. Not sure if I want to mess with all of that. I'd hate to fry something if that's possible. I understand that the stations will have to be broadcasting their digital signal at the same power as their analog in a few months.