Fairly basic HD DVR questions

[Gladius]

I've had DirecTV for a few years now, and have recently upgraded to HD service. We had the new dish and a plain HD receiver installed recently but I was put on the "wait list" for an HD DVR. They said 2-3 weeks but it's been over 4 with no word...so we're getting restless missing our old Tivo.

I'm wondering if
a) I have to use the DirecTV DVR (once I actually get one) or can I buy a "third party" DVR;
b) If I can get a third-party unit, do I use the simcard out of the HD receiver or do I have to get DirecTV to somehow activate the new/non D*TV DVR?
c) If I can use a third-party DVR, what would you recommend?

Thanks!

[SFS97]

I would call D*, heard stories of them never calling the cust back.

a) There is no third party HD-DVR right now. HR20- thats it. You could get a HR10-250 (tivo)off e-bay and activate it, but I don't think that would be worth your while.
b) see a..
C) see b...

[DawgLink]

I was told 3-4 weeks for 1 month

I then called once a week and on my 2nd try...was told magically they had a bunch in stock

Call every other day, imo