The first thing I would do is upgrade your SQL from 2005 to at least 2008 R2 or 2012. Backup the DB, detach it, install new version of SQL, then re-attach and configure as needed.
After that, then I would do the upgrade to ePO 5.1.1 - go through this KB to make sure you have everything met before doing the upgrade.
I'm not sure I understood you exact question, but the upgrade is pretty straightforward and simple from 5.1 to 5.1.1
I have an update on implementation of Epo 5.1.0 to 5.1.1, and let me know what are the main methods to perform the upgrade.
thank you for your support.