Hi and welcome to the Forum!

That's a little weird, have you reset your iPad after the upgrade, it is a recommended step. So I'll get you to do this as a first step and see how it goes. Hold the power off button and the home button simultaneously, keep holding them in and you will see the power off slide appear and disappear, wait until you see the Apple logo appear before releasing the buttons. It will take a little longer for your iPad to start. Let us know if this has fixed the problem.

The IPad Forum is a community of members from all walks of life and from all over the world coming together to share our experiences and to help each other learn about this wonderful piece of technology the Ipad. There is a wealth of information already here in the many threads we have so doing some searches will answer most of the questions you have. If then you cannot find the answer you are seeking then by all means post your question. There are many friendly and informed members here only too willing to help you.

We also have our own App - It is a very simple app to navigate.
http://itunes.apple.com/us/app/discussion-forum-for-ipad/id412896524?mt=8
Reading the IPad manual is a great place to start so please download a copy of these.
http://www.support.apple.com/manuals/ipad/
2 very informative threads from which you will learn many tips and shortcuts for the IPad.
http://www.ipadforums.net/ipad-general-discussions/21590-tips-tricks-those-us-who-dont-know.html
http://www.ipadforums.net/ipad-os/49581-ios5-tips-tricks.html
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http://www.ipadforums.net/forum-rul...um-rules-everybody-please-read.html#post14697

Once again we welcome you here and are so pleased you have joined us!

Sent from my iPad using iPF

How about something slightly more drastic, connect your iPad to your computer and restore it from the back up?

The Archangel

And to add with thewitt's comment- have you tried to contact your carrier to see if maybe the issue is with them? There was a previous thread regarding loss of 3G connectivity and many of the recommendations related to carrier issues.

Also see this thread. It is from 2010, but look at the the tips regarding settings and having to reset.
See here: http://www.ipadforums.net/ipad-help/13727-how-get-3g-back-ipad.html