I would definately buy a white wig for this one.
When I first started dying wigs, I always used Katie Bair's stuff. I think her website is still katiebair.com. The stuff works great, but it can get pretty pricy if you need multiple colors. It's about 20$ a kit, so only 2 colors will obviously set you back around 35-40$. For an easy first time wig dying experience, it's worth it.
I just began mixing my own wig dyes and I'm still working on a definate formula. I've broken up sharpies, squeezed out the ink and used that (I believe I mixed it with warm water to lighten the colors). I've also just become familiar with a new method using callgraphy ink. If you buy some bright colors of ink at your local art store, you can take a few drops of that and mix it with rubbing alcohol to make a simple dye. Put the mixture into a spray bottle, and spray away! You just have to wash the wig when you're finished to get rid of the alcohol smell. I actually like this method the best because it's pretty cheap, and Sharpies can get pretty messy.
For you're wig.. like I said before, I would buy a white wig to start. Cut it to match the style of the character, and then seperate the hair into 2 seperate layers, a bottom layer and of course a top layer. Simply clip and pin the top layer up, and maybe wrap some scrap fabric or a towel around the hair to protect it from the dye. Dye the bottom layer of the wig, let it set for a little white, rinse it out, and let it dry. Then start with the top layer in the same method as the bottom.
Goooood luck! Dying wigs is an interesting experience!
