Vijay,
Someone from Vertex can help you by providing an estimate. They just need to have a 30-minute conversation with you about your tax situation. The implementation can take from 2-3 months for just Order to Cash process integration or 4-6 months if you add in Procure to Pay process integration. Vertex can help you with this as well as many of their implementation partners.
If you tell me what company you are with, I can point you to the appropriate Vertex Rep who can help you.
Thank you.