Man, that's a pretty old machine you have there! Any idea on when it was made? As far as the paper scenery behind the monkey goes, there really is no replacement for it unless you make one yourself (or get someone to do it for you).
Maybe if you could get a close picture of the paper someone here could help out.
Also, since that game is so old, you may just want to consider keeping the current paper on there. But its really up to you.