Poker Stars No-Limit Hold'em, $0.05 BB (6 handed) - Poker Stars Converter Tool from http://www.flopturnriver.com

SB ($6.15)
BB ($2.40)
UTG ($1.97)
MP ($4.06)
CO ($7.98)
Hero (Button) ($6.28)

Preflop: Hero is Button with 9, 9
2 folds, CO raises $0.15, Hero calls $0.15, 2 folds

Flop: ($0.37) A, 2, 9 (2 players)
CO checks, Hero checks

Turn: ($0.37) 2 (2 players)
CO checks, Hero bets $0.25, CO calls $0.25

River: ($0.87) Q (2 players)
CO bets $0.30, Hero raises $2.20, CO raises $5.82, Hero??


What do you think villain's river raising range is here?