Tell us what model and brand that your power supply is. If you only come back saying it is 450w and nothing else people won't like want to take the time to help. Cheap power supplies make for a lot of headaches and lost time.
Second the other limiting factor for this card will be the pci-e slot as power is usually limited to just 75w per pci-e slot while some allow for up to 95w but it is usually unlisted.
Beyond that you are on your own when it comes to final clocks. Get msi afterburner if you get that working and give it a try.