Lesbian couple trying to conceive

My partner and I have been together for almost 5 years and have decided that we want to expand our family (I have a 10 year old daughter) i started tracking my ovulation. It my cycle are so inconsistent ( I can go months with out one) and I am in nursing school so my stress levels are pretty high most of the time. I started taking a prenatal vitamin and have heard wonderful things about the dietary supplement called "Vitex". Has any one else heard of it or has tried it with success? Are there any other tips for trying to concive? We are going through a sperm bank and frozen sperm only survives 24 in the body Vs. from sex with a male partner. Thanks in advance