LOST ALL MY IMPORTANT TEXT MESSAGES HELP iPhone 3G

PLEASE, if anyone can help me recover all my text messages I just lost from all my clients for the past 2-3 years I will greatly forever appreciate your help. I have been on the phone with Apple support and carbonite and I cannot find my recent backup before the 4.3 upgrade...Please anyone can help me. If I do a system restore on my computer could it restore the backup on my iphone? These text messages are my life of my business. I know it was absolutely dumb not to back up the text messages another way, just have not had an app to do this. Help!!
iPhone 3GS Windows Vista Just did 4.3 upgrade 3 days ago.