I think what you have is correct. I have come across it before as well, and I think it's lovely.
Ummm I pronounce it differently but I'm from the UK where there is a river Avon pron. A (as in ape)-von. So I say A-von-lee. I only realised I said it differently when discussing Anne of Green Gables with my Aussie Chiropractor who says Av-on-lee.
I quick Google search gives me both pronunciations but I do prefer the way I don't say it! :)
Your pron. is correct.
I pronounce it the same way you do. :) Friends of ours just named their baby Avonlea but they call her Avey for short.