Do you have to report profit from sale of a real estate? Some were spent to pay for charges on remodeling?

I sold a house in 8/2003 with large profit and has been unemployeed/student until now. I didn't report the profit in 2003 and bought a house 8/2005 with that profit. I'll start work next month and like to report taxes but afraid I may be taxed on previous income. And I don't have receipts of remodeling costs, they're lost during move.