Cordoba rear suspension

[aerohydro]

The rear end of my 95 Cordoba has gone rather squashy (begin jokes now). The height when unloaded only looks a little low but when there's any weight in the boot or back seat the thing scrapes over any bump or dip. I have a tow bar fitted which reduces ground clearance and takes the scrapes. What do I need to replace to get the rear end firm and high again?

Thanks.

[Golf Loon]

New shocks. Or decent shock and spring package.
I have some at work if you are in need.