You are basically going to need a 2400 VA single-branch circuit ups system with a battery bank, inverter/charger, wiring and control. The inverter should be a full sine wave type with a built-in transfer switch. This is for one 20-amp circuit only. Going with one more circuit would require a 4 or 5 kVa unit.
You may want to look at a company called Xantrex (www.xantrex.com) which sells quality inverters. Look under inverters/chargers. I have not dealt with them so I cannot offer any insight with respect to the cost. Try contacting them directly to set you up.
You may want to look at a company called Xantrex (www.xantrex.com) which sells quality inverters. Look under inverters/chargers. I have not dealt with them so I cannot offer any insight with respect to the cost. Try contacting them directly to set you up.