Ususally - but not always - this type of connection loss can be 'fixed' using a few tricks. The first is to reset both your modem and your router - disconnect each from mains and let them stay unplugged for about 5 minutes (if you've a modem with a battery backup, as I do, there should be a small reset button on the back of the modem). Plug in the modem first and then the router next.
Then go to System Preferences>Network pane and select Wi-Fi. Click the Advnaced button and get rid of all remembered networks. Then add your 'new' network connection back.
If this doesn't solve the problem, call back...
The same happens to me, at home and at school. I will be connected then all of a sudden the web page fails to load saying there's no connection to the internet. The only way to fix it is what Jesushelpme said and yourself, but those methods only fix it temporarily. I have other devices constantly connected to these networks with no issues, but it seems the connection will work for about 10 minutes then stop working while still connected, and it is getting very frustrating, especially depending on my macbook pro for school and such. If there is any other solution you can think of I would appreciate it, as I know many other people having the same issue with their macbook pros, and everything I've been told to try already only fixes it for about an hour.