A 12 gauge shotgun will do you wonders.

Really though, the MG is a very hated amp here, everyone is going to tell you to get a new amp, might as well. If your low on cash, then I would recommend the Marshall Class 5 tube amp, it's like $300-$400 and it's pretty loud for a little 5 watt, then there's the Blackstar HT-5, great amp for metal.
i for one used to use an mg. and the distortion wasn't exactly "great." so, before i got a new amp, i got a boss mt-2. while it didn't make the amp sound a whole lot better, it did get me more into the metal territory. as a fellow mg (former) user, i would say that if you really only want stronger distortion, get something relatively cheap, maybe a digitech pedal. then, start saving up for a better amp.
All the way from Palm Springs, just out of detox.
Show him a warm welcome, let's hear some applause