Will dividing a room (adding a wall) increase a homes value?

I'm almost done doing improvments on my first home that I purchased in 2007 and want to sell to get the most I can at this time - housing recession. Its a 1600 sq. ft. bungalow house but only has 2 bdrms upstairs, so will further dividing the bottom level of my home (combination family room/dining area) to add a bdrm or office into 2 split this area help add to the value of an appraisal? or make no difference and be a waste of time/money?