Could you tell us a bit more about your current broadband set up?
If you are using cable or ADSL.
Do you connect the modem via USB or RJ45 to the PC?
Depending on your current set up then you may have a couple of different options.
I use wireless to connect a couple of PC's and my Xbox360 to the wireless network - it works great. I'm on ADSL and use a D-Link 624+ router/modem.
I also bought higher gain antennas to improve the signal.