What do you mean by "grab"?
Why do you need the portal?
Is the due date a field in the related table?
A portal can be set up to show all records where the text field that auto-enters the account name matches the account name of the user. You just need an unstored calculation field: Get ( AccountName ) to use as the match field in the layout's table.
If you then specify a portal filter to check for records that have a due day from today's date to 7 days into the future, you have your list of related records and no script is required to produce that group. (A different relationship with some unstored calculations can also be used instead of the portal filter.)
On the other hand, a scripted find can pull up a found set of the same records and not need a portal nor a relationship to do so.
i figured out my mistake
now I just need to figure out how to write the calculation
CurrentDate <(lessthan or Equal to) DueDate
Get ( CurrentDate ) < RelatedTable::DueDate
But that doesn't match what you specified in your first post.
Let ( T = Get ( CurrentDate ) ; RelatedTable::DueDate > T And RelatedTable::DueDate + 7 < T )
would return True if the the due date is in the range from today to 7 days into the future.