Look at L'oreal's OleoTherapy line to complement your Marvelous Oil hair product. Oleo shampoo is meant to glide across the hair shaft and norish hair with ingredients that revive hair and create new follicles. Use it as often as you want as there is no problem with oily hair from it or problems because it is too harsh as it's not. I advise trying to use it several days a week to get hair in better shape and also a very sudsy shampoo for volume for luxurious hair that will withstand styling products and pollution.
The conditioner is also a great product. It is always helpful to condition hair in time to close the hair shaft and is a good product to keep the shaft smooth. These products are good especially for reviving hair of dye jobs, smooth hair for a good flash of shine, keep hair just plain healthy and also one more thing - keeping your cut together and making your mind perfectly healthy as far as your hair so you are happier with your haircut.
Oil products are so good to keep hair as great as it can be so if you are having problems try it and also use it often for hair that already healthy to protect hair again bad chemicals and dirt.
See these products at a store like Wal-Mart or a grocery store in your area.