If you cannot get any fans/ac to cool down your house/the room you keep your gecko in, then you need to AT LEAST find a small fan and aim it directly at the side of the tank that is your established "cool side".
Also, make sure that the cool side of your tank is kept shaded, so prevent as much heating as possible.
And be sure there is a constant supply of fresh and cool water for your leo.
But you do not want to let your leo get too hot. if it overheats it can get really stressed out - and if the heat/stress is too high, your gecko could die of overheating/heat exhaustion.
The absolute BEST thing you can do is invest in a few good fans or at lease one good ac. when you are using those, if you find that your hot side is starting to cool down too much, just use your gecko UTH (which of course should always be on) or overhead light to give it the extra boost of heat.