Whether you now pass the VCP4-DCV exam and gain that certification or not, you will need to take a vSphere 5 class in order to qualify for VCP5-DCV.
You have the option of taking the What's New class for vSphere 5 as you attended vSphere 4 training, or you could take any of the other training courses that qualifies for VCP5-DCV.
If you look at the graphic on the link below you currently have Row 1 and Row 3 as your options, if you pass the VCP4-DCV exam you will have Row 1 and Row 2 as your options - either way you'll need to do vSphere 5 training.