Mini cart on Marketpress

I know this has been covered before and I have tried to find/bodge a solution but any chance someone can write a plugin or addon for Marketpress that shows a minicart. Perhaps in a widget? I tried taking the code from gridmarket for quantity but it would not refresh.

Also all we need is a one liner: Your basket 2 items - £150

or just: 2 items - £150

for example.