Widgets - Filter based on Start dates

[Jim]

Hi, 

I have created a widget which will show me the predicted hardware to provide however, I would like it to only show me the hardware required for the following week where h_custom_21 (being a users start date) is between start of next week and end of next week or current week maybe?. 

 

I did try the common SQL in the filter but it doesn't like that on the widgets for some reason, Could someone please advise how I could achieve this?

 

for example 

 

[Jim]

any help on this would be much appreciated