Debbies:

There is no direct conversion of Quickbooks to Sage 50 to include history. There are 3rd party developers who can accomplish this feat but there would be a cost. I am guessing about $1500. and upwards.

To convert Quickbooks to Sage 50, only accounts, vendors, customers, inventory & employees can be imported. From there an opening trial balance of ledger accounts need to be entered, then balances from each period would have to be entered for each account to do any comparative reports in Sage 50(basically journal entries) for the history required. My suggestion is to either work with Quickbooks or start with Sage 50 and gradually accumulate data to run comparative reports. We can help if you need assistance.

Thank you for your response.  This confirms what I have been able to to gather from other sources.  I've started a Sage 50 file for this client to pass on to the new bookkeeper and will give her excel format files of quarterlies to stitch together with Sage data for comparatives in the short term. 

typically sage will do import for free- however its important to keep both running for interim to make sure things are kosher and not missing