User has large amount of emails -- issue with archiving Outlook 2003

We have Exchange 2003 and Outlook 2003 on all PCs.  One user has over 35,000 items (approx 4.3gb) on exchange server.  This is what happened...he decided to archive his email, but put the "archive" on his H:\ drive (home drive).  Now he has two 2 "archive" folders displayed in Outlook.  Evidently, at some point in the distant past he archived and evidently put it in the default location on his hard drive.

As a result of the above...Outlook is slow to open, slow or "reply" or "forward"...I assume it is because the 2nd archive resides on a network share.  

I want to clean up this situation.  I want only one (1) archive. How can I combine both archives?  I want to use the archive on the local PC rather than the network share...as I assume it will speed things up.

Additionally, I assume at some point in the future he will archive again and at that time he should use the existing archive on his local PC...yes?  which will, combine this future archive and the existing one.   Is there any size limitation to the archive.pst.

Sorry to be so long-winded...I wanted you to know all the details.  Many thanks in advance for any guidance you can offer.