Security cameras?

Does anyone here have any advice on a security camera system?

I've got a Swann system, DVR8-4500, and I think the fan is having an issue because it's making a lot of noise. I actually unplugged it last night because I was concerned about it starting on fire. When one gets dependent on a security system, one feels very insecure without one.

I had an issue with a crazy person a couple of days ago and I'm kind of worried he'll come back, so I really need to find a solution quickly.

Anyhow, my options are to buy a new DVR, which will take a few days to get here, or to buy a new system. This one is wired in and I really don't think I can handle crawling up into the attic to try to put in new cameras. Ok, I KNOW I can't do that. So I'm thinking I should try a wireless system. I don't need anything for inside my house, just the outside. Does anyone have any recommendations on a decent wireless system with night vision?

I'll probably take apart the DVR today and blow it out really good. I don't know a whole lot about compatibility of fans (if that's what the problem is). I'm sure my son could figure it out, but he's at work all day and also it's Valentine's Day and he needs to spend the evening with his wife.

Thanks for any help you smart people can give me.