The little 4-banger TJ's aren't really known to put-out vasts amount of heat, but you can check:
-your coolant level and condition
-your waterpump, blowermoter ,and thermostat are in working order
-check to see if your blend doors are not stuck shut
-make sure your clutchfan isn't siezed or it will be on all the time, and pulling cold air through the rad
Do you have carpet in your TJ? Get some Dynamat or other insulation under a carpet and you can even insulate the hardtop.
When all else fails you can always put a piece of cardboard in front of your rad.