Your Access query must return a single value
Menu : Data Get External Data New Database Query..
In the Dialogbox click on the Database page (default) and select "MS Access Database" and click "OK"
In the next dialog box select the location of your database (.mdb). The another dialogbox is opened containing the list of available tables and queries of your database. Then select your query and follow the steps of the wizard
When finished, you have in the Data menu a new option to "Refresh Data".