Defining/Protecting hands with Pot-sized bets or Overbets

[quarkncover]

No reads on villain, just sat down at table a round ago. My question is, When is it appropriate to bet the pot or overbet the pot in a HU situation such as the one below? I recognize the situation is very read dependent. Therefore I am looking for a standard line here against an unknown. When HU or 3-handed I usually bet 1/2-2/3's the pot here. Do I bet more, maybe even overbet on the flop or turn, as I usually bet the same amount on continuation bets? I know river call is way out of line not even getting 2-1 on my money, curiosity calls are a real leak. Finally, what hand do you put villain on? Comments on all streets appreciated.

PokerStars No-Limit Hold'em, $0.25 BB (9 handed) converter

UTG+1 ($49.70)
MP1 ($36.35)
MP2 ($24.40)
MP3 ($24.90)
Hero ($24.65)
Button ($37.70)
SB ($18.95)
BB ($32.80)
UTG ($20.45)

Preflop: Hero is CO with A[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/spade.gif[/img].
<font color="#666666">1 fold</font>, UTG+1 calls $0.25, <font color="#666666">3 folds</font>, <font color="#CC3333">Hero raises to $1</font>, <font color="#666666">3 folds</font>, UTG+1 calls $0.75.

Flop: ($2.35) 7[img]/images/graemlins/spade.gif[/img], 5[img]/images/graemlins/club.gif[/img], 2[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
UTG+1 checks, <font color="#CC3333">Hero bets $1</font>, UTG+1 calls $1.

Turn: ($4.35) T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
UTG+1 checks, <font color="#CC3333">Hero bets $2</font>, UTG+1 calls $2.

River: ($8.35) J[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
UTG+1 checks, <font color="#CC3333">Hero bets $4</font>, <font color="#CC3333">UTG+1 raises to $17.5</font>, Hero calls $13.50.

Final Pot: $43.35