5NL Low 2 pair facing river raise

[foal]

I figured his calls indicated some kind of pair and his river raise indicated he'd made aces up. Then again he could have just been making loose calls with AK or something. Fold?
Also I think I should have bet pot on the turn considering I had a low 2pair and there was a possible straight draw too.

Poker Stars - No Limit Hold'em Cash Game - $0.02/$0.05 Blinds - 6 Players - (LegoPoker HH Converter (http://www.legopoker.com/hh))

SB: $3.23
Hero (BB): $9.93
UTG: $3.18
MP: $6.68
CO: $8.31
BTN: $7.50

Preflop: Hero is dealt T/images/graemlins/club.gif 3/images/graemlins/spade.gif (6 Players)
2 folds, CO calls $0.05, BTN folds, SB calls $0.03, Hero checks

Flop: ($0.15) 8/images/graemlins/spade.gif 7/images/graemlins/club.gif T/images/graemlins/spade.gif (3 Players)
SB checks, <font color="red">Hero bets $0.15</font>, CO calls $0.15, SB folds

Turn: ($0.45) 3/images/graemlins/heart.gif (2 Players)
<font color="red">Hero bets $0.35</font>, CO calls $0.35

River: ($1.15) A/images/graemlins/heart.gif (2 Players)
<font color="red">Hero bets $0.85</font>, <font color="red">CO raises to $2.25</font>, Hero ?

Pot Size: $5.65 ($0.25 Rake)

[monkover]

I´d call here. imo a big part of villain´s range are overs or Ax fd that made tp one the river. river raises usually do mean significant strength, i´d still call though.