Firstly you may want to check over at xda developers for an aftermarket ROM for your phone. They're free of carried installed bloatware and tend to be more up to date (with Android releases). If you go down this route backup your phone first.
From memory I recall the SMS data being stored in a SQLite database. Tools exist in perl to parse this data, see sms-grep.pl, further reading Finding and Reverse Engineering Deleted SMS Messages, and Creating a Perl script to retrieve Android SMS.
Update: added first link.
