I find it difficult to imagine that Braun would not want to export their product to the USA so if it were me, I would try contacting them direct to see what they have to say.
Their website is www.bbraun.co.uk the telephone njumber is (0114) 225 9000 & fax (0114) 225 9111. although I don't know what the international code would be.
Failing that, I made my own irrigation pump which was not very difficult to do and worked out very much cheaper than the professional model (although I'm not knocking Braun)
I did do a review on their previous version of the irripump if your interested. It's on my blog list dated 08-17-12. I feel sure that the latest version will be an improvement on that!
As for the stoma plugs. The ones I use are from Coloplast and I'm almost sure that they trade across the water.
Good luck and best wishes