OS X V10.7 Lion :: Filling Up The External Hard Drive So It Only Kept Backups For A Few Weeks?

OK, kinda a long story. Pardon the ranting, but if feels like everything is going wrong and I'm getting pretty tired of it. 

I was going along nicely with my Mac. Then I had a time-sensitive iMovie project that was going totallly screwy. I ended up buying Lion hoping that would fix the problem. It didn't spent several more hours trolling forums and figured out it was a weird problem with the software. 

So... then I was stuck with Lion. Photoshop, Dreamweaver, Rosetta Stone, etc. don't work on it. Not cool. Would have been nice if I was warned before doing this. So, I figured I'd go back in my Time Machine backup. However, I was really busy and didn't get to it until a few weeks later. I'd never actually used Time Machine, but when I went into it I was astonished to find that it backed up on the hour, filling up the external hard drive so it only kept backups for a few weeks. And of course, it was too late to backup to my old OS. So not cool. Who in the world needs an hourly backup??? I'd much prefer a weekly backup a little further back. That's just absurd. 

So, anyway, I had the old Time Machine backup. I figured if I messed up, I could always restore to the recent Lion backup. So, I restored to Snow Leopard from the disk, wiping the hard drive. Then, I tried to go in and get my files off of the external hard drive/Time Machine backup. It didn't recognize I even had an external hard drive plugged in. 

So... I decided to go back to Lion, maybe I needed to be in Lion to access the Lion backup. Spent hours putting Lion back on. And... still doesn't even recognize that there's an external hard drive plugged in. What gives? 

I've been trying to think of what all could be the problem here. Did I just think I was backing up to the external hard drive this whole time, when really I was backing up to the computer? No, because it would send me reminders when the external hard drive wasn't plugged in. Is the cord or something broken to the external hard drive? I suppose it's possible, but just a few hours before I saw the Time Machine backups... And there is power to it.