Answer:
0.125 or 12.50%
Explanation:
Since the couple already has a child with albinism and both parents have skin pigmentation, it can be concluded that both parents are heterozygous (A, a).
With that being said, there is a 1 in 4 chance, (a, a) genotype, that their next child has albinism, and there is a 1 in 2 chance that the child is a girl. Therefore, the probability of the next child being an albino girl is:

The probability is 0.125 or 12.50%.