Painting advice

[medsecslave]

I've just moved house and have taken the wallpaper off a bedroom wall with a view to painting it instead. Where the paper was joined in some areas it had begun to lift back from the wall and now that I've taken the wallpaper off the underlying paint in those same areas is lifting off to reveal the original plasterboard. Is it best to apply polyfilla then paint and does it need a basecoat? Any advice appreciated. Thanks.
ps -never decorated in my life before as you can tell!