It is very possible for a woman to re-establish a milk supply even when her baby is a couple of months old.

• Re lactating is about teaching or re-teaching your baby to nurse at the breast. The aim is to create a sense of comfort with the experience and to feed as often as possible, even after a bottle feed or when they have just woken up or fallen asleep.
• Milk production is associated with two primary things – nipple stimulation and milk being removed from the breast. As soon as your breasts begin to produce milk and milk is taken via your baby (or pump) your breast received a signal to produce more. For this reason the more you feed or pump the more effectively your breasts will increase their milk supply. 
• Re lactating can be achieved by using a pump regularly. Milk can then be given via a cup for example.
• While it may be easier if your child is only a couple of months old, many women have had great success with older infants also.
• Women re-lactate for many reasons. Sometimes it is a digestion issue while other women simply change their minds or want to experience the emotional element of breastfeeding. It provides a lot of support, comfort and security to their children and they want to experience it.
• There are a number of herbal remedies which can be taken to help increase your milk supply if you are trying to re-lactate. Fenugreek is one such thing. You can speak to your local health food shop about the different options available.
• If you are considering re-lactating it would serve you well to contact a Lactation Consultant. They will have seen it all before and will be able to advise you accordingly.