How do I keep my pot of tulips growing healthy?

I got a pot of tulips for valentines day this year. They were absolutely beautiful. Notice the past tense... Were. The past week or two, the flowers have fallen off and the leaves have started to turn brown. How do I keep the flowers alive and what do I do to make them grow back? I don't want the memories of this vakentines day to fade away and die like my flowers are.