'Dirty' Harry Callahan said it best: "Every man's got to know his limitations"
It's not what you KNOW, it's what you know you DON'T know. When in doubt, find a pro. You may be able to find someone who'll work with you, but generally speaking, tradesmen prefer to be left alone. Ever seen this sign?
- Repair Service - $20/hr.
- Letting you watch - $25/hr.
- Letting you help - $30/hr.
- You already tried to fix it - $40/hr.
You get the idea...
Sounds like you're definitely going to need a sub-panel. Make it at least a 125 amp service (about the smallest breaker panel box you can buy). It'll require running some bad-axe-mother-fletcher cables from your main box. Best way is to bury it underground. Since they're going to be burying cable anyway, when they run the big conduit, go ahead and run a separate 3/4" conduit alongside it. You can probably do that part yourself. Then you can run things like telephone, cable TV, alarm wires, etc. to your garage. It's better to have them in a separate conduit to reduce interference, and it may be required by code, I don't know. You can bury the conduit and leave a pull string (or two) inside it until you're ready to add wires.
There's lots of rules about adding sub-panels and underground wiring, so it's best to let the pros handle it. That said, they'll be HAPPY to let YOU dig the trench!
c.