Eventually, as the child gets older, your friend will once again be able to devote more time to you. Be accepting and patient during this stage. Nature demands that your friend give most, if not all, of her attention to this new little one. The baby's survival depends on this. Best to you.
Every friendship goes through life changes.
A smart friend will adjust and accept these changes, rather than fighting to make things the way they were. You might be surprised and just end up enjoying having a new baby around.