wanna give up coffee

My big problem is I always drink coffee whenever I work on computer even I am not sleepy at all. Unfortunately working with a computer is my job so that I dont drink coffee in the weekend only. Sometime, instead of drink coffee, I force myself drink tea or pure water but after that I still go to buy coffee even though I told myself many times that dont drink coffee more... It is not good when drink coffee a lots, especially for women, then I wanna give up it, but How? Could anyone give me a hint to help me.