Can someone help me edit one photo

I have a photo of a seagull that I want to order a large print of (50x70 or larger).
Its going to be printed out on a canvas on "fabric".

My problem is i dont have enough water on the edges and on top/bottom. Because the edges of the photo will be wrapped around the frame.

I tried editing in more water and centering the seagull a bit, but it looked awful :/
So can someone help me get more water on all the sides?. Perhaps centering the seagull a bit so that his wing is not so near the edge?
Full raw file (33mb)
http://btfoto.no/gull.​tiff
small jpeg version:
http://btfoto.no/image​s/IMG_4574.jpg ( old awful version with to much sharpening, just so people see what it is before downloading the original)

I'm not sure if this is any better than you have been able to accomplish but...I made a rectangular selection with soft edges and then stretched it with transform. Then did some cloning on the edges to blend them.
The top I had to make two selections and combine them, then the same procedure.

This was done rather quickly, I'm sure it could be improved upon.

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Thats really good! Did you do this on the raw file?
I would love to get the original so i could print this in large!