Help- Moving Illy Image to Photoshop?

I know I know, I shouldnt do this. But for now I need to just for a quick mock up. But when I save my illy image as a PNG24 with transparency and use place or just copy and paste my Illy image (now in Photoshop) looks really pixelated. It doesnt seem to matter what size I save the original vector image always goes fuzzy?

Help...can I do? Apart from not do it in the first place!!

Cheers in advance...
Much easier to just copy whatever it is from illustrator directly into photoshop. Don't bother saving it as a PNG24 in Illustrator, then placing it. Just copy and paste it directly. Just make sure the image in Illustrator is big. Because if it's small you cant enlarge it. Much easier to transfer a big image that you can shrink.

What is the image by the way, a logo?
You say it is a vector file, so instead of saving it as a PNG to open in Photoshop, why not just save it as an EPS to open in Photoshop? Won't slow you down and will be as crystal clear as you wish.