Hi, not sure of any books but there are some good websites online such as
www.babycentre.com which have loads of articles about this sort of thing.
I think the main thing I read is it is important to prepare your toddler for the new arrival that way he won't be jealous. There are many things you can do to ease the transition for your oldest son. These are things like including him in the preparations by letting him choose a toy or blanket to welcome his new sibling. I think it is also important to make sure when they meet for the first time the new baby is not in your arms and you cuddle your toddler instead. That way he will know he is still special to you. You could also buy him a small present and say it is from his younger brother or sister.
In terms of you managing what is that you are worried about ? There is a great book called The Contented Little Baby book which myself and many of my firends swear by. It may be a little too regimented but you can adapt the ideas to your own needs. I found it fantastic for establishing routines with the new baby to make sure the house ran smoothly and there was time for everything that needs to be done.
You can also prepare you helper by sending her on a training course and sharing your books with her so she knows exactly what you expect from her and where she can support you. Annerley midwives run first aid and baby care courses for helpers and Ladybird lessons run child development and child care courses.
I hope this helps.