If you do not already gave DirecTv service, you can set up the install through BB/CC when you buy the Tivo unit. You will need a SAT dish with at least a dual LNB and you will have to have two cables running from the dish to your Tivo, since the Tivo is a dual tuner (can receive two programs at the same time.) If you are going to add another unit to the bedroom, you may as well do it at the same time. Some plans don't charge anything to install up to three rooms. You can have a plain receiver in the bedroom, which will cost you an extra five bucks a month.
The extra receiver probably won't cost anything to buy. You might consider going ahead and getting a second DirecTivo for the bedroom. It still won't cost more than five dollars extra per month (I'm pretty sure...)
and then you could record up to four different shows at the same time!
Regardless of what you choose for your second receiver, you'll need to have a multi-switch (sort of a fancy splitter) installed between the dish and the two receivers. I don't believe there is an extra charge for this if done with the initial install.
So basically, you could get a two room install (one Tivo and one plain receiver) including dish, multi-switch, and cables, for $100. OR with two Tivos for $200. Tivo service will cost five bucks per month above your basic monthly service. The extra receiver will cost another five bucks, regardless if it is a Tivo or just a plain receiver, because, I believe, the Tivo charge is per house, not per receiver.