You can swap miles between some airlines on
www.points.com. It looks like BA only permits you to buy their miles via that site, but AA and Delta allow swaps. Maybe AA would work? Be warned you will surely use a lot of miles this way. Using those miles on a DL, KL, or AF flight would be a better value.
As for Hilton points, keeps your eyes open for another promo like this:
http://www.britishairways.com/travel...0/public/en_ca