I put a 30 amp plug outside because I have the same problem. You can't run the AC on a regular extension cord.
I'm lucky enough to have my electrical panel outside, so I just picked up a pigtail like you would use for an Air Conditioner (6ft 3 wires with connectors which is sold in the same aisle) and a 30amp breaker. For about $50 total and 30 min of effort I now have full 30amp service at home.
If you're not handy, it's worth hiring a handyman or electrician. wouldn't take anyone more than 30 min unless they have to run wires through walls.