Yes, you have version 4.3. There are 4.5 versions out there for CDMA phones (such as yours and mine on Verizon), but... they are BETA versions. Personally, I'm waiting for the final release before upgrading.
Your call though. Search the forums if you want to find the 4.5 for CDMA curve versions.
I agree with our resident 'Genious of Geniuses' here. Your OS (go to Options, About, 3rd line down) is fairly recent. It can record video for instance, mine cannot.
I would wait for 3 reasons.
1). you are failry new to Crackberry and are only just familiar with your phone. Do't mess with it until your have asked a few more questions in here.
2). Any unreleased (beta) software you obtain for your phone will certainly have software bugs. Do you want this?
3). You can easily invaidate your warranty by doing an unsupported upgrade.