Might want to sort an exhaust line out for the fumes. I had the same problem (no power in garage) got some armoured cable and hired a jack hammer, buried the cable I did all the wiring (except to the RCD unit) and got it checked and tested.
Now got 240V @ 40A - spread over the garage in multiple sockets. I was a days effort but still cheaper than a generator assuming that you do allot of the work yourself. (and cleaner).
Just need a little sofa and wide screen and I am set.