Even though your idea is noble, as a rule, egg donors must be healthy women between 21-34 years of age. All the eggs that a woman will ever have are produced by about six months of age while she is still in her mothers uterus. No new eggs are produced after this time. At six months, there are about 4-5 million egg and this number declines to 1-2 million at birth, and by puberty there is less than one million eggs. The number of eggs rapidly declines, and at the time of menopause only a miniscule number of eggs remain.
The age associated decline in fertility (and increase in miscarriages) is largely due to abnormalities in the egg itself, less frequent ovulation or to problems such as endometriosis. Not only do the number of eggs decrease, but the quality of eggs also are compromised by genetic changes, either chromosomal breaks or more subtle genetic changes. Therefore, in women over 40 the pregnancy rate declines dramatically and the spontaneous abortion rare increases. Some studies show the abortion rate in over 40 women to be over 50 % due to this. There is an increased incidence of chromosomal abnormalities with one in sixty live births being genetically abnormal. There is also a greater chance of bearing twins.
You can be helpful in many other ways by joining a group that deals with infertility and being active with them.