FYI: All Olivia Cruisers that are going on our trip are more than welcome to order T-shirts, hats, or whatever from that website under my account as well! So all you lurkers, or new arrivals to the Forum, you can also use the below instructions. We are all in this together after all!
I set one account up simply to save everyone the hassle of emailing back and forth and then having to upload the logo themselves (and be charged additional $$ to do that). We have lucked out by doing this too, in that we have been able to take advantage of the special pricing that they keep offering us for our "continued repeat business"...which is great for all who still need to buy their t-shirts!
They are really great quality for just $4.74, and can be washed! Many of us already have ours. 
~Bunny