Add an image to my site

Hi would like to add this video from istock to my home page:

http://www.istockphoto.com/stock-video-8889299-pal-pharmacy-sign.php?st=56da4fa

Need confirmation if it can be done. We have on www.betterchemist.com an "ask our pharmacist" button on the left hand side with "Free Medical & Health Advice". We want to keep the "Ask Our Phatmacist" title but replace the rest with this
istock icon.

It is a quick job, if you do it well you will get repeat work from me.

If you can do it, you need to let me know which size i need to buy from istock:

320 x 240 px @ 25 fps

640 x 480 px @ 25 fps

720 x 576 px @ 25 fps

Thanks Al