How come it looks like the picture was taken through a periscope?

Anyway, I have a couple suggestions. Basically you'll want to make the brake function as well as you possibly can, short of buying a new wheel. Set the pads correctly, or maybe buy some new high quality pads. Clean the rim with soapy water or alcohol. Sanding the braking surface might wreck the paint, but I've never had to do this so I'm not sure. Hope this helps.