It cannot be retrieved like you think nor is there a specific upgrade since you are dealing with two entirely different platform types.
QBSE is single entry and the rest of quickbooks is double entry. Unless you exported to excel and entered the second half of double entry prior to import you are guaranteed to lose data.
That being said - you still have 365 days of reports only access to QBSE and you could have exported transaction lists to excel before cancelling your QBSE.
If that is not enough you can resubscribe for a month to retrieve individual data snippets but do use copy/paste between multiple open browser windows to migrate your missing data