Difficult Spot, Check raised with flush on river. HU

[Zamm]

Played about 100 hands with this guy before this hand came up. For the most part he was super tight, ive played with him before. I would just like to know whats your play in this same situation, CALL, FOLD, RAISE?? Thanks

PokerStars Game #11638607832: Hold'em No Limit ($0.25/$0.50) - 2007/08/22 - 22:10:15 (ET)
Table 'Lamberta III' 2-max Seat #1 is the button
Seat 1: Grinder3030 ($128 in chips)
Seat 2: pkrockets23 ($56 in chips)
Grinder3030: posts small blind $0.25
pkrockets23: posts big blind $0.50
*** HOLE CARDS ***
Dealt to pkrockets23 [6c 9c]
Grinder3030: raises $1 to $1.50
pkrockets23: calls $1
*** FLOP *** [Ac 3c 5s]
pkrockets23: checks
Grinder3030: checks
*** TURN *** [Ac 3c 5s] [3s]
pkrockets23: bets $3.50
Grinder3030: calls $3.50
*** RIVER *** [Ac 3c 5s 3s] [7c]
pkrockets23: bets $5
Grinder3030: raises $10 to $15
YOUR PLAY

[ceire]

looks like a full house to me but i think i call

[Zamm]

ok well i lost the rest of the Hand history but he ended up have A 7... for top two pair. So i definilty feel like i missed a value bet on the river