oracle sql embedded in excel external import data with variable filename

I am importing external data in Excel with the folling parameters:

Provider=MSDAORA.1;Password=xxxx;User ID=xxxx;Data Source=xxxxx

Command Type = Table

Command Text = xxxx.tttt

I need to have a user promt in which a user identifies a work order, and then have the Command Text adjusted to reflect the filename associated with this work order.

Example:

Provider=MSDAORA.1;Password=xxxx;User ID=xxxx;Data Source=xxxxx
Command Type = Table
Command Text = datasource.table1

after user types in table2 in prompt, the query should read:

Provider=MSDAORA.1;Password=xxxx;User ID=xxxx;Data Source=xxxxx
Command Type = Table
Command Text = datasource.table2

How do I set up the Oracle filename as a variable to be updated with a prompt box?

Thanks!