How do I handle these situations? NL$25

[Miraculix]

Hi.
I have some problems knowing how to play accordingly in situations like these. These two hands came within 10 minutes yesterday and about 15 minutes before that I lost almost a buyin (with KK!) against a calling station hiting his 2-outer on the river, so my confidence was a little low....

Hand 1: Villain is 28/8 over 83 hands.

Cryptologic
No Limit Holdem Ring game
Blinds: $0.15/$0.25
5 players
Converter

Stack sizes:
UTG: $22.81
CO: $29.10
Button: $10.35
Hero: $28.25
BB: $32.55

Pre-flop: (5 players) Hero is SB with K[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/diamond.gif[/img]
UTG calls, <font color="#cc0000">CO raises to $1.5</font>, Button folds, <font color="#cc0000">Hero raises to $4</font>, 2 folds, <font color="#cc0000">CO raises to $18.5</font>, Hero??


Hand 2: Villain is 47/11 over 36 hands so...

Cryptologic
No Limit Holdem Ring game
Blinds: $0.15/$0.25
6 players
Converter

Stack sizes:
UTG: $28.61
UTG+1: $20.20
CO: $5.70
Button: $5.40
Hero: $24.75
BB: $26.75

Pre-flop: (6 players) Hero is SB with K[img]/images/graemlins/club.gif[/img] K[img]/images/graemlins/spade.gif[/img]
<font color="#cc0000">UTG raises to $0.75</font>, UTG+1 folds, CO calls, Button calls, <font color="#cc0000">Hero raises to $4</font>, BB folds, <font color="#cc0000">UTG raises all-in $28.61</font>, 2 folds, Hero??

Do I call here and pray? It seems like AA to me but then again, I´m a bit weak-tight sometimes.

Greateful for any help.

// M