Connection Issues

For the past two weeks or so, I've been having a problem with my connection.
While playing games, I'll occasionally hit a huge lag spike. In some games (League of legends, Counter-Strike) I'll just lag for a bit, then go back to normal. In other games (Battlefield 3, Crime Craft) the game will kick me, telling me I can not connect to server. In the games that kick me, I can reconnect seconds after I am disconnected.

I've contacted ATT support (My ISP), and they've told me to call them while the problem is occurring. Which isn't possible because it only happens for 10-15 seconds, and it takes 10 minutes to get on the phone with them.

I have a Motorola 2247-N8. It connects to the wall through a standard DSL cable, and the modem connects to my computer with a standard Ethernet cable.

If you need any more info, I can provide it.