Watch the Outlining G7 online guitar lesson by Fareed Haque from Bebop Improv Survival Guide
The basic chord, arpeggio and scales on G7. Here the alternatives, the choices become so deep it can be dizzying! So check 'em out one or two at a time. Chose a few sounds that you like and stick with them for now, and eventually you can add more combinations of extentions as you get bored with the ones you are using.
The chart here gives a number of examples of arpeggios and scales that are commonly used with a dominant chord going to a minor chord.