Hi and welcome!
I am sure your device runs v1.5. Here's how you check:
Settings -> About phone -> Firmware version
That will probably say "
1.5".
If you want v2.x, there's a stickied
thread just for that. In reality you will need the
mustymod custom rom. I have no experience with it, so proceed at you own risk.
If you want v1.6, the community just got hold of it the day before yesterday, so it's still very untried. But many of us are actively trying it. One tip: if you want to switch, switch soon -- you can't take your settings with you, so it's a fresh start. The earlier you switch, the less you will have to redo.
Either way, beware: even though updating your firmware is very well described in various stickied posts, the process is rather long and you might get lost on the way. Sorry, but them's the breaks.