Exit stratagies

Hi all
a query on exit strategy. I bought a house 3 years ago with a return of 13%, with improved capital value the return has dropped to 6.5%. I base my return on the purchase price plus costs of the property, I have been advised that this is incorrect and that I should be taking the cost of money into account etc. I must admit to a case of confusion as to what I actually should be doing. Like everyone else I am in this to make a quid.
What are the thoughts of the forum?

Steve [confused][confused]