Television DVR HDD

OK here’s the thing:

I have, use, like, am very satisfied with, a Panasonic DMR-E85H, with a 120 Gig hard drive.
Works fine for editing, and writing DVD’s.

But 120GB isn’t nearly enough for all the accumulated (stuff) on my DirecTV DVR. Or even much for uncompleted WIP. The DTV DVR is about 25% filled, I have no idea what that is in GB; I’m about ready for my 2-year switch between Dish and DTV for a lower price contract. I’m quite sure the DTV DVR will turn into a brick (their brick) as soon as the contract is cancelled, and I lose all my stuff.

And I know cows will fly before I manage to replace the 120GB drive in the Panasonic with a 1TB or bigger drive.

So my question is this: 1TB drives are really very reasonably priced; what is the most reasonable way to set up bulk video storage with a 1TB or larger external hard drive?
I don’t need a tuner, editing capacity, burner, VHS drive, or anything other than bulk storage with an index of stored videos, with video input/output; the Panasonic works fine for all those other functions. And the DVR’s currently offered have somewhere between poor and hideous customer reviews for usability and dependability, and there goes $300 and up for something I can’t depend on.

I’m reasonably proficient with a soldering iron, if there’s a way to construct a video connection to an external HDD; I’m completely hopeless at writing or altering software.

Any advice much appreciated, Thanks!