If you're at Kwun Tong you pretty much have two options:
Closest is Kowloon Tong, a few stops on the MTR, prices are reasonable and you can find quality if you shop around ... but it involves a bit of a sweaty walk ... definitely the #1 option if you're driving.
A little better is Villa Victoria in Tin Hau. Right next to MTR, with a front entrance and a back entrance (take your pick), good quality and fair price.
Alternatively if you really want Kwun Tong get onto
www.booking.com (or a similar site) and see if the hotels in the area are discounting. Won't cost you a huge fortune, especially if you're up for a longer session, and you get the advantage of no time limit.