Change partitions?

[Ed Jabbour]

Current partition table:

sdb1, primary .............................. empty
sdb2, primary .............................. backup files
sdb3, ........................................... extended
sdb5, logical ................................. ubuntu installation
sdb6, logical ................................. swap

I'd like it to be:

sdb1, primary .............................. ubuntu installation
sdb2, primary .............................. backup files
sdb3, primary ............................... swap

If possible, I want to avoid re-installation of the OS.  Is there any way just 
to change the partitions, leaving whatever is on them intact?  gparted's copy 
won't do it, I hear.  Any hints, pointers, etc. greatly appreciated.