Hi All you Geniuses out there!

Please help! I'm no tech-smarty, so I need some guidance. I made a trailer for my movie that has a size of 1280 x 1080 (16:9). Footage was originally shot 1080i60. I know I'll lose a lot of resolution upon placing on the web. But, my question is how do I import my .flv file or .mov file and keep the size intact? Flash seems to squish my picture so all my images are narrow to fit in a 3:4 format.

What can I do? Please describe in easy steps to me... I am eternally grateful!