I want drums but.....?

First, what climate is it where you live? If it is very arid, or can get very cold (such as Arizona, or Québec) putting them in a non-climate-controlled garage could be a bit damaging to them. At the very least, they would go out of tune quite a lot. So this should be looked into.

If this is all fine, don't worry about the neighbours. A good tip is to put thick-ish towels over the drumheads (I used to use fluffy hand towels from Home Outfitters), and a pillow in the bass drum. This dampens their sound while still keeping the general tone, so you are able to hear your drums, and people walking by the house will be able to hear your drums, but the surrounding houses won't hear a thing.

Another option you have is an electronic kit. These don't make a sound except if you have headphones on, and you could probably fit one in your bedroom, as they're more compact. As well, they have the benefit of not requiring new drum skins or such, which can be very, very expensive. Electronic kits can be hooked up to speakers for gigs and hooked into computers for easy recording. BUT there is a downside: they do not have the "feel" or sonic diversity that an acoustic kit has. You can't be as imaginative on them, essentially, which sucks.

Good luck with drumming, man! :)