Graphic logo looks rough

Any idea why my logo looks rough?

It was produced in Illustrator and saved at 350 x 350 pixels (and placed at this size) I’ve tried uploading a .gif and .png version but get the same result.

The logo is white on a transparent background.

I tried placing an .eps and .ai file but it said I couldn’t as there ws a ‘security issue’

How can I show a crisp and clean version of my logo?

Many thanks.

The page I need help with: [log in to see the link]