Router to track bandwidth usage?

[cross]

Hi everyone,
Been gone a while..

Anyway, I have a LOT of people in my house right now, all with wireless laptops.
I've seen a HUGE amount of bandwidth used in the past few days (8-16GB a day) which is unusual for my household. This is a problem for me since my ISP has a monthly traffic cap.

I've started the usual things, doing virus/malware scans and whatnot, checking for unknown connected devices (using encryption on router), but since I need to replace my wireless router anyway since its very dated:

Are there any routers out there that will track bandwidth usage by IP or MAC or some other individual identifier so I can identify the culprit? I'm thinking either its an infection i'm not finding, or some one is doing some heavy file sharing against my wishes!

I'm not so concerned about lan vs wan traffic, since I'm the only one really transferring stuff internally, so I can cross my IP/Mac off the list and take that into account manually...

Do these routers exist for a home type network? I've just started researching, but am only finding old articles and Cisco stuff so far, so I'd like some advice!

Thanks!

Wasn't sure where to put this since it isn't security related per-say, but please move it if you think it fits somewhere, as I'm sure it'll get more attn in the appropriate section!