help with historic photo restoration

I'm working on a photo of a building from the late 1800s. The edge of the roof has a grainy halo around it. I'd like to extend this texture to the corner of the photo and eliminate the white background currently there. Can anyone suggest the best way to do this? Thanks for any help!

Use the clone tool...

I tried clone & healing brush, but got ghosts and unevenness. It's a delicate grain and all that stamping shows, and the healing had a muddy look. I was thinking I could sample a small consistent area and then use a gradient - I'm just not sure how to go about it.

Ok, forget the gold swapper above:-)
Tell me would you have a scan of the pic so I can take a look and if you could show me the area you want to expand...
What size is the picture? Might be able to play with that...
You know... If the pic is large then we might be able to reduce a copy of it and pick up some "Glow" from one and put it on the copy etc...