When mental of buying a router, you have to take any things into observation before production a financial commitment. First of all, there are these new routers and modems - combined into one product. However, it is always best to have a router and modem separated so that when your router disconnects, you won't have to disconnect your modem.
Now, you can always buy online or just go to a computer hardware shop. It depends what you want to do and who you trust.
When seeing at buying a wireless router, you don't have to spend a huge of whole of money to buy one. You could buy D-Link RangeBooster N 650 which is both a modem and a router. And it incorporates the new technology with N connectivity allowing you to associate to a network in a big house or office and at faster speeds, depending on your Internet assistance Provider.
If you decree to buy a router and modem separately, then I suggest that both the modem and router be from the same company so you will have less problems. Also, make sure you buy a wireless adapter to associate to your network - again make sure all things is from the same company so you will have fewer problems connecting your hardware together.
So, for example if you buy Belkin router, make sure the modem and wireless adapter are also Belkin.
Almost all modems and routers have same quality so it doesn't admittedly matter what brand you buy as long as you receive a warranty and a good product.
How to Buy a Good Wireless Router