Sorry if there is any confusion.... my bike is running a 53 -42 up front and a 13-18 rear cluster

im not barely making it up the hill, (of which there is only 1 on my daily commute) im mashing like a mad man and sitting on about 17-18kph, but i would like it a bit easier as by the time i get to the top my legs are gone and my hearts jumping out of my chest.....

my first choice would be to change the rear cassette but im not willing to spend much money on this bike as its a bit of a mongrel thing that i got cheap, every dollar spent on it is a dolar i could be putting towards a decent roadie.. so i guess i'll take a look at swapping the smaller chain rings