When To Fold?

[inspectorgadget]

PreFlop: SSJBurn is BB with Ah Ts
3 folds, Button calls, SB calls, SSJBurn checks,

Flop: (3.00 SB) 6h 4d Th (3 Players)
SB checks, SSJBurn bets, Button raises, SB calls, SSJBurn raises, Button raises, SB calls, SSJBurn calls,

Turn: (7.50 BB) 8s (3 Players)
SB bets, SSJBurn calls, Button calls,

River: (10.50 BB) 7c (3 Players)
SB bets, SSJBurn calls, Button raises, SB calls, SSJBurn calls,

Final Pot: 10.50 BB

Should I fold that river? Also, should I raise preflop here? I would usualy raise preflop with ATo w/ better position...