The Repeat control is in different places, dependant on which model of iPod Touch you have.
On my 2nd gen Touch, if you tap the Now Playing screen an overlay drops down from the top of the artwork. This overlay has the time-bar (with elapsed time on the left and remaining time on the right ends of the scrubber bar, and below that (on the left side) is the Repeat icon. If the icon is in white, then Repeat is off. If the icon is in blue, the Repeat is on. If the icon is in blue and has a 1 in it, the iPod is in Repeat 1 mode (repeat just one song).
It sounds as though your iPod is in Repeat 1 mode. Tap the Repeat icon to turn from Repeat 1 to Repeat off.
On the right hand side of the scrubber bar, just below the remaining time, is the Shuffle button.
Some later models of iPod have a bigger repeat button, accessed by dragging up the Now Playing screen. It's colours may be white/red, rather than white/blue.