So you are attempting to migrate from Invision (a php/mysql application) to Xenforo (a php/mysql application).
With this free program (sql buddy) and a database username/pw for READ ACCESS you can look at the database schema of both applications and figure out how to map the data.
http://sqlbuddy.com/
Each user in Invision clearly has a database field that contains the "member's total reputation" and another database field that contains the total number of posts. It is just a matter of finding the corrosponding fields in Xenforo and importing from Invision to Xenforo.
In my opinion, this should be done with Xenforo installed on a completely different domain: whatever.com
Once you see that all has gone well and whatever.com looks the way you want, then you just point the domain name huskerboard.com over to the whatever.com and delete whatever.com.
For that matter, it could be done in a SUBFOLDER of huskerboard.com (huskerboard.com/xenforo/) and when the operation is complete just repoint huskerboard .com to /xenforo/ as the root folder. Everything else would remain the same underneath that.