I am purchasing a used netbook from a friend. I want to purchase a router because internet signal is not strong in my area. Do you have to use the same brand router as the wireless card, eg. Belkin router/card, can you mix, for instance, Belkin/Linux?

You can mix and match. There's really no need to stay with the same brand. For example, some companies make better routers than they do wireless cards and vice versa. Do some research and get what you like.

Yes you can mix and match but I'm curious as to what you mean by the signal not being good in your area? Are you talking about a satellite service or something, in which case how would a router help?

I'm also curious as to whether they meant modem and not router...or maybe a wireless signal repeater, to strengthen the signal or something? In any case, yes you can mix and match, and I wouldn't recommend Belkin personally.