First off, before we go any further,what version is your iPad (iPad1 or 2, WiFi only or with 3G)? Has it ever been jail broken? Is it used or did you buy it new?
All these questions are necessary because the stock answer is that, no, the iOS you have cannot be jail broken and you cannot load iOS 4.3.3 on your device any longer (Apple closed that window back in July).
There are some caveats to this, which is why we need all the info you can give us about your specific device.
Thanks.
Marilyn