Add on to kickboxing

I started kickboxing 3-4 times a week about a month ago and am happy with the results. (Lost 2 pounds and 4 inches). What I'd like to do is incorporate some weights for my days off so I can punch and kick harder. If anyone has any suggestions for the best way to do this I'd appreciate it. For reference I'm a 5'4 female, 168lbs. I'm kickboxing at a kickboxing gym and burning approximately 500ish calories in the hour according to my Fitbit. I have 3 and 5 pound weights plus the my husband has hand weights that you can add plates to add 10, 15 or 20 pounds to, a curl bar, and a bench. I don't want to spend any $ on more stuff so hopefully this is enough to work with.