About 220 watts for 220 amp/hrs is a good place to start depending on use.
Next is to figure out what fits where on the roof. You need space to prevent shadows from vents, antenna, air conditioner etc.
Then consider MPPT (high voltage) or PWM (nominal 12 volt). MPPT controller allows simpler series install and often lower cost 24v panels but the controller is a premium. PWM you can oversize the controller and add panels in parallel as needed.
Here are some to look at:
Forum Members Solar Installations With PicsIf this is a DIY be sure to post the the primary equipment to verify all is compatible.
Some prices on panels and controllers can be found here. Pick up in Norco and save the shipping.
www.solarblvd.com