What should be my action on the river here?

Transcript for last 1 hour of play requested by ripjgarcia (ripjgarcia@hotmail.com)
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PokerStars Game #22194133853:  Hold'em No Limit ($0.10/$0.25) - 2008/11/19 22:32:11 ET
Table 'Normannia II' 9-max Seat #6 is the button
Seat 1: ripjgarcia ($21.10 in chips) 
Seat 2: henningwww ($17.10 in chips) 
Seat 3: Joefkgpoker ($19.10 in chips) 
Seat 4: L3NGTHY ($25.45 in chips) 
Seat 5: helios25 ($27.85 in chips) 
Seat 6: Smokeyjo ($13.10 in chips) 
Seat 7: GoStros5 ($31.90 in chips) 
Seat 8: green45 ($30.45 in chips) 
Seat 9: Samirah333 ($20.85 in chips) 
GoStros5: posts small blind $0.10
green45: posts big blind $0.25
*** HOLE CARDS ***
Dealt to ripjgarcia 
Samirah333: folds 
ripjgarcia: raises $0.75 to $1
henningwww: folds 
Joefkgpoker: folds 
L3NGTHY: folds 
helios25: calls $1
Smokeyjo: folds 
GoStros5: folds 
green45: folds 
*** FLOP *** 
ripjgarcia: bets $0.50
helios25: calls $0.50
*** TURN ***  
ripjgarcia: bets $1.50
helios25: raises $2.50 to $4
ripjgarcia: calls $2.50

The river was the