aspect ratio and format frustration

I have FCP 7 and have a video that is 1920x1080 Apple Pro Res 422 LT. I need to provide the client with a final file that is 300x250 FLV for display on the client's website. The video is just a single camera shot, head-on, of a person sitting at a TV desk - so cropping shouldn't be a problem, we won't lose anything important. But I can't figure out how to get the final size that I want, let alone how to get a Flash file (I have Flash installed on another computer - a PC.) What should my workflow be? Thanks in advance.