If you buy this in the hope that you have a good gaming card you'll be disappointed. It's not.
I would go for at least a HD6670, HD7750/7770 or a 7850. ( depending how good that 450W psu is. )
I agree. That card wont give you satisfactory performance. If you can try and get HD 7000 series card as it consumes less power that 450W PSU should be able to handle it.
I guess the HD 7750 doesnt even require external PCIe connector. It draws power from the PCIe slot itself.