Water pump

I have a 1988 Daihatsu Charade CLS (hence the usename) with 135k miles and the water pump needs to be replaced. Is it easier to take it in and have it dont because it looks like the engine needs to be lifted out of the car. I dont have the tools for that. Or can I do it without lifting the engine. I recently replaced the thermostat and that helpped the temp a lil but it still gets hot when driving on the freeway or running the a/c. So I have been suffering out here in the hot utah weather with the 2/60 a/c. Do you suggest flushing the cooling system before replacing the water pump? If you could let me know I would REALLY appriciate it! Thank you much!