When it comes to getting the right color down, you always have the option of mixing your own.
For a while now I have not used primarily GW paints, as I found they were a tad on the "rich for my tastes" side, when it is possible to get more water-based paint for cheaper, and usually in better variety, at an art store. Also, the benefit of checking out a store like that (I'm not sure which ones are in your area) is that the staff can help you find the right color you are looking for, and just help in general with getting the right gear.
In general, it is much thriftier to get your painting and modeling supplies at an art supplier than through GW.