I'm fine with getting a new power supply. I know it's a shame. Just remembered i've got a student loan coming in at the end of the month. Combine that with christmas and £150 is probably the most i'd spend. Maybe add £20 if it's worth it.
That looks good to me. Is there any difference between the model if it's made by MSI, Saphire , ASUS etc.? I know someone who sells computer components, unfortunately not upgrades like sound/graphics card, so the power supple should be a bit discounted. I've noticed there's quite a big jump between price between the £90 range to the £140. Sucks.
MSI is a good brand, in the top brands AMD overall (ASUS, Sapphire, Gigabyte and MSI) and that 7770 is a ghz edition(means it's overclock to 1000mhz).
About the psu, it's the best price i see for a quality(xfx is a good brand) psu 450w.