set on flop, calculating odds.

I have PT and Poker Ace, and am now focusing on taking the time to calculate odds and figure no better way then to go through PT and take the time to calculate the odds on random hands. I decided to drop to .25/.5 to focus on gaps in my game, and although the suckouts and passivity is killing me, it's forcing me to discipline myself since I know I should be able to win at this level (Fundemental Theory of Popker). This is from a set of 2's on the flop.

PokerRoom .25/.5

Seat 1: BB
Seat 2: UTG
Seat 3: UTG+1
Seat 4: UTG+2
Seat 5: MP1
Seat 6: MP2
Seat 7: MP3
Seat 8: Empty
Seat 9: Button - Hero [ 2[img]/images/graemlins/club.gif[/img],2[img]/images/graemlins/diamond.gif[/img] ]
Seat 10: SB
ANTES/BLINDS
SB posts blind ($0.15), BB posts blind ($0.25), MP2 posts blind ($0.25).

PRE-FLOP
UTG calls $0.25, UTG+1 calls $0.25, UTG+2 calls $0.25, MP1 calls $0.25, MP2 checks, MP3 folds, Button - Hero calls $0.25, SB calls $0.10, BB checks.

Although I've tended to start folding pocket deuces in early position, no one has shown strength and with this many limpers, I'm hoping for a set. If I don't hit a set, I'll fold to a bet.

FLOP [board cards 4[img]/images/graemlins/club.gif[/img],2[img]/images/graemlins/spade.gif[/img],Q[img]/images/graemlins/club.gif[/img] ]
SB checks, BB checks, UTG checks, UTG+1 bets $0.25, UTG+2 folds, MP1 calls $0.25, MP2 calls $0.25, Button - Hero bets $0.50, SB folds, BB folds, UTG folds, UTG+1 calls $0.25, MP1 calls $0.25, MP2 calls $0.25.

I hit my set. The only possibly made hand I may be losing to at this point would be someone with pocket fours. Although PT has the others as passive, I doubt anyone would have limped with pocket Q's. I'm putting the others on top pair or a flush draw. I raised to chase out the SB and BB who limped. I doubted that the previous limpers would fold, and by representing a hand, hoping that the flush draw and/or Qrag would fold on the turn if they don't improve.

TURN [board cards 4[img]/images/graemlins/club.gif[/img],2[img]/images/graemlins/spade.gif[/img],Q[img]/images/graemlins/club.gif[/img],8[img]/images/graemlins/spade.gif[/img] ]
UTG+1 checks, MP1 checks, MP2 checks, Button - Hero bets $0.50, UTG+1 calls $0.50, MP1 calls $0.50, MP2 calls $0.50.

The only hand I would see improving is someone playing a Q8s which is possible at this level, but I'm still ahead. Everyone checked to me as I hoped, so I lead out and bet.

RIVER [board cards 4[img]/images/graemlins/club.gif[/img],2[img]/images/graemlins/spade.gif[/img],Q[img]/images/graemlins/club.gif[/img],8[img]/images/graemlins/spade.gif[/img],7[img]/images/graemlins/diamond.gif[/img] ]
UTG+1 checks, MP1 bets $0.50, MP2 calls $0.50, Button - Hero bets $1, UTG+1 calls $1, MP1 bets $1, MP2 calls $1, Button - Hero bets $1, UTG+1 calls $1, MP1 calls $0.50, MP2 calls $0.50.

Now I didn't expect that many callers on the turn, but the missed flush makes me feel my set holds up. The bet on the river has me baffled, but I continue raise and then reraise.

1. Was my postflop/preturn thinking correct or should I have simply called since raising would still have given the flush draw the needed odds?

2. Should I have simply called on the river since the better hadn't shown strength at all throughout?

3. Any other errors in betting or reading the table?

Thanks.