Wall Bed assistance to reduce the lift weight

Hi everyone, first of all I'm not an engineer but I enjoy solving problems and have re-built my apartment from scratch in a very small space (30sqm), so everything has 2 or three functions.

One being the wall bed which I took a standard mechanism with slightly stronger springs in the hopes it would handle the weight I put on it. I mis-calculated and now it's a little heavy to lift up and down. I added two tables that fold down off the bottom of the bed (when the bed is in the closed position), and wanted a full sized mattress instead of the average ones they usually recommend with wall beds.

I've attached some images of the mechanism and bed design from the manufacturer. Basically, I need to find a way to reduce the load when lifting and lowering and would love to hear your thoughts on it.

Thanks so much for taking a look.

[ATTACH=CONFIG]1005[/ATTACH][ATTACH=CONFIG]1006[/ATTACH][ATTACH=CONFIG]1007[/ATTACH][ATTACH=CONFIG]1008[/ATTACH][ATTACH=CONFIG]1009[/ATTACH]

I assume that the spring set already has a full set of 9 springs. If you know the spring rate of the current springs then I suggest you go to a spring manufacturer's website such as "Associated Springs" and check out their catalog for "In Stock" extension springs to see if you can find one with a higher spring rate of similar closed length to your existing springs.
Note: When selecting a new spring be sure to check that its maximum allowed extension is equal or greater than the extension length of your springs when the bed is open. (What you will be looking for is a spring equal to your current ones but with a larger wire diameter.)

Thanks for the fast reply, yes they're loaded up with 9 springs on each side currently. I will try and find out the spring rate and hunt down a suitable spring as per your suggestions with a higher spring rate.