My buddy replaced his with a Ruger orange/red painted from site. Easy to change out yourself and pretty cheap. The orange/red stands out much better than the white.
It's under $20 at Ruger.com
http://ruger.com/webapp/wcs/stores/s...lastCatId=null
If you don't want to replace it, but some painters tape and some Birchwood Casey sight paint. I've done too revolvers with it and have had good results. Be sure to tape every thing off you don't want paint on and make sure the tape is on secure.