If you saved database before upgrading, then install the WP/BP versions you had working with that DB and import the database to the installation. Then deactivate all plugins except BuddyPress and change to Twenty Eleven theme before upgrading WP/BP to current versions. Activate bp-default theme after the upgrade and check everthing is working before activating plugins (which you should check if compatible with latest BP/WP versions before activating).
If you only saved database after the upgrade, then that’s a different story. I do hope you backed up DB before upgrading.
