welcome to the world of ladies problems, ive got long hair and its a pain to wash so i only really wash it twice a week what ever time of the year it is. if i wash it any more it just goes greasy and needs washing more. i wouldnt start washing it any more than you do now, you can get a product called dry shampoo from boots
http://www.boots.com/shop/product_de...ductid=1012075
start washing it every other day use this inbetween and it shouldnt need washing as much.
xx