Sum of a range corresponding to the current week

Hi all,

I am currently trying to update my works team tracker - we have an overview section at the top of the page which uses a simple countif formula for each person to show their utilisation for each day.
What I would like to do is show their percentage utilisation for the current week next to the persons name (column B in attached spreadsheet) for this I need it to lookup the current week based on the values in row 2 and then sum up the totals from the corresponding countif formulas - is this possible?

Many thanks in advance.
RH