Welcome aboard Johnathan. If you used a GT11/31 the data should be on the machine iteslf even if not retrievable from the card.... hopefully one of the smart people will read your post and tell you how!

30.9 on you first GPS run: nice going

To retrieve your data click on "Data Logger", then select "Save to card".  This assumes you've set up your GT11 / GT31 properly... Please refer to this page:

http://gpsteamchallenge.com.au/guides/setupgt11_2008.php

Losing a days session is the sort of thing that we've all done, but usually we only do it once