If you are allowed to reformat your table slightly, you could use the following formula as your conditional formatting check. I placed the formula in all cells of the table so you can see what your two values evaluate to on the table. If you cannot split your table headers apart slightly then you need to modify the formula to ripping out the numbers from the string in order to make the comparison.
This is the formula I placed in all cells starting with top left cell in D5
=AND(AND($O$5>=D$3,$O$5<=D$4),AND($P$5>=$B5,$P$5<=$C5))
If you are stuck with a having to use the strings in your header and need something that looks like this:
then use following in cell D4 so you can see how it evaluates and copy it into your conditional formatting for a new rule:
=AND(AND($O$4>=--LEFT(D$3,FIND("mm",D$3)-1),
$O$4<=--MID(D$3,FIND("-",D$3)+2,FIND("m",D$3,FIND("-",D$3))-FIND("-",D$3)-2)),
AND($P$4>=--LEFT($C4,FIND("mm",$C4)-1),
$P$4<=--MID($C4,FIND("-",$C4)+2,FIND("m",$C4,FIND("-",$C4))-FIND("-",$C4)-2)))
NOTE: When setting up your conditional formatting rules, have all your entries selected and make sure the top left cell of your selection is the one with the whitish background.