Gravitar from Champions Villains vol 1 has a similar power:
Altered Gravity Field: Flight 26m Usable As Attack (does not affect anyone with Desolidification, Power Defense, or gravity-manipulation abilities; +1¼), Ranged (+½), Area Of Effect (16m Radius Selective; +1)
Perhaps to create a field that lingers use something like this; anyone entering floats straight upwards:
Reverse Gravity Field: Flight 2m, Ranged (+1/2), No Gravity Penalty (+1/2), Reduced Endurance (0 END; +1/2), Uncontrolled (Set effect, straight up; +1/2), Area Of Effect (16m Radius; +3/4), Time Limit (5 Minutes; +3/4), Usable As Attack (Defense is Density Increase, Desolidification, Power Defense, or gravity-manipulation abilities, grabbing something will prevent further upwards movement but not negate unless character can be pulled outside radius of field; +1 1/4) (11 Active Points)
Add Increase Mass advantage a few times to boot to lift heavy inanimate objects too.
To be honest, I don't really see how Power Defense would resist this so I'd probably skip that one.