A 5450 will generate roughly 10 mhash/s stock, if I remember correctly. In general it will not be much better than a CPU, 5x faster at most. More with extra flags
It's a dedicated HTPC card made mainly for decoding high definition movies so it's not very powerful.
edit - yes, ~11 as the chart shows
With guiminer, the 5xxx series cards should support -v -w28
With phoenix, you'd use BFI_INT