To update the WON version to 1.5 you can look at google. Here is the result that I got -
http://www.ausgamers.com/files/details/html/2464
If you want to update to 1.6 you can install Steam -
www.steampowered.com. When you install it just type your retail key and you will get CS 1.6, HL, OF, TF and some other HL1 based Valve mods.