...what about the numbers to the right of the radix point?
You simply group them into groups of four digits, just the same as you will group digits to the left of the radix point, and translate each group of four binary digits into a single hexadecimal digit.
With digits to the left, you include leading zeroes as necessary to complete the groupings of four digits. With digits to the right, include trailing zeroes as necessary.
I'll work a different problem, leaving your particular example ($66.25$) for you to do yourself:
With groupings of four binary digits each:
Converted to hexadecimal: