Unless the upgrades to the problem software have an added benefit it's hard to justify the cost just so it will run on Vista.
You need an XP Pro CD & license key (from any machine) to do the upgrade. If you can find an XP Pro cd & Pro COA key from another IBM/Lenovo it should go in and not have any activation problems since the mfg string in the BIOS matches the key. If it fails the activation you just call the MS licensing mothership and tell them you're doing an "XP downgrade" and they will activate the install.
If you can't find an XP Pro CD search torrent sites for "XP 9N1" - it's a modifed XP install that has every version (Home,Pro,MC) in every licensing model (Retail, OEM, Corp). Just install the one that matches your key type and then change the key once it's up and running.
I've done this a few 100 times for clients, ask any questions you have.