Alltel Phone on Cricket Network, Need Rom Update Help

[nFiniti]

I just recently bought a Alltel PPC-6700 for 175 NEW with a free 512mb sd card at a cell phone company that went out of buisness. Then I had it flashed to the cricket network since Alltel wont touch me (bad past!). And I want to install the newest ROM update. I called the place that put my phone on the Cricket network and asked them if it would revert my phone back to Alltel or anything at all that would require me to re flash the phone (which costs 60 bucks) and they didn't know really. And from all the reading I've been doing on these forums from the Howard Forums Wiki, it seems like THIS is THE place for the proper info.

So to the question. If I do the newest ROM update, will I lose my network and need to re flash? or does it have anything to do with the network settings?

Also, one more. How can I backup my contact list without installing Outlook?