Predicting a foal's color is "iffy" at best-- so many criteria to take into account, and even then, something "hidden" or unknown can show itself and surprise you. For example, a buckskin can carry the "red" gene, so if it does, not only can they produce black, bay or buckskin, but they can produce a sorrel too, if they carry it.
Is the brown and white mare the one in your avatar?
You have a darn good chance for a pinto (tho not a CERTAIN one); you could get brown, buckskin, black, sorrel, or even others. Are you excited yet?