I'm new to the forum and have only just read your post so I guess that you may well have found a supplier... or taken out the bank loan!!
If you haven't done either yet then you could try
http://taiteuroturbos.com/Taits are specialist suppliers of new and re-conditioned turbos and can also supply repair kits for most makes such as Holset, Garrett, Switzer, KKK, IHI, Cummins and Mitsubishi.
I have good experience of them from the day-job. We needed a turbo for a 10.8 litre, 290 horse power loading shovel engine. Cummins needed 10 days to supply as they only had stock in the US but Taits had one in stock that arrived next day and at half the price.
Martin