Which program that uses the bandwidth the most?

So, my boarding house internet connection has been down for 4 days now, and I decided to find alternate internet connection. On Indonesia it's really hard to find mobile internet provider that has unlimited bandwidth without FUP. I decided to use one with limited quota (8GB/month) T__T seriously.. 8GB it's my daily usage, not monthly. So I buy a router with modem support (TP-Link Wireless N Router TL-MR3420) a modem (Huawei E173) and GSM card for internet (Three). Long story short, I want to know which program that uses so much bandwidth since the beginning, so I install nethogs). That program should be used as root, and the first argument is default to eth0. Nethogs will show the list of process that uses most bandwith.