If you need to meet some short term spend requirements, definitely buy some coins and buy some gift certificates for merchants that you'll otherwise use in the future.

Costco cards sounds like they'd fit for you. Buy them now, spend as you normally do.

Also, there is a way you can buy American Airlines gift certificates through a two-step process that nets you more than one point-per-dollar for the AA spend. Search the AA forum for a post about a guy looking to spend 4,500 on AA. Its laid out there.