Ive uploaded it to my picture server...now go to this page on your iPhone 4, and simply hold your finger down on the picture below and hit save...voila, you can use it on your iP4. You have 24 hours before its deleted from my server...
I just tried it for sh*ts and giggles and it looked fine to me...
...fyi, you could have simply emailed it to yourself on your iPhone and done it that way as well...as far as making it look "HD", how exactly would you expect a person to go about that when the source itself is what you gave us? You want some magic HD pixie to come along and sprinkle it with HD fairy dust?