Hi Kirsty
That's a decent time, especially for a first 1/2 marathon.
Knees are what runners seem to injure most, I suggest you get some decent shoes that support your feet the right way (if you haven't already), and try to do regular stretches particularly ones that strengthen your knees
Strapping doesnt seem to do much unless there's swelling, a physio can tell you what you've injured, & how to fix it / stop it coming back
