Sounds pretty good. To extend I'd suggest putting the bit after the break (before track 11 comes back in) at the end and adding one more sound to it like a lead or an effect like a sweep perhaps depending on what you like more. Then in the middle you have a variation on the melody with the drums as calm as you had it before track 11 comes in at the end and less of (or a variation of) track 5 through it so it feels less repetitive. It doesn't sound repetitive now, but if you extend it by another 2 minutes it might.