Villain is a donk.

didn't want to donk bet the flop since i didn't want to fold if raised, and anything other than a minraise by villain and i would have folded.

The turn was a great card so i lead out, though any card that wasn't a 2/6/10 and i would probably c/f turn.

Bet sizing on the turn ok? What size bet should i make on the river?

Hero: ($400 in chips)
Villain: ($1137.35 in chips)
4 other players

*** HOLE CARDS ***
Dealt to Hero: [Ad Ts]
1 fold
Player 2: raises $8 to $12
Player 1: calls $12
Villain: calls $12
1 fold
Hero: calls $8
*** FLOP *** [Td 6h 2c]
Hero: checks
Player 2: checks
Player 1: bets $16
Villain: raises $16 to $32
Hero: calls $32
Player 2: folds
Player 1: calls $16
*** TURN *** [Td 6h 2c] [2h]
Hero: bets $48
1 fold
Villain: calls $48
*** RIVER *** [Td 6h 2c 2h] [5s]
Hero: ?