If you only have a 3Gb drive then I assume your data is less than that, so if you use backup to desktop rather than backup2ws, it should work OK as long as the resultant backup file is less than 2GB. Use a non Microsoft browser for better handling of large (2Gb) files ie Netscape or other
Backup2ws should also work OK but there was a problem with restoring all data, you need to put a second entry in the job in order for everything to be restored correctly (search for backup2ws in these forums for the appropriate thread I started).
Note that with any of the backup/restore methods, you will still need to reinstall any rpms/programs that you added to your original server as these are not generally part of the backup.
Cloning the disk from one disk to another should be quite easy and it will include everything that you have installed on the server, the only thing to be aware of is that the original installation loaded appropriate drivers etc for your hardware in the original box. The new box may have different hardware and therefore the most appropriate drivers may not be installed. Having said that I have done similar on a Pentium 166 box and then put the drive in a Celeron 600 and it worked quite OK.
Theoretically, backing up, loading the OS on the new machine and then restoring from the backup is the most reliable way although you need to reinstal all add on rpms as well.
Regards
Ray