I agree new inner & outer cables will make a difference. From the picture it looks like you're already using modern brake shoes, although avoid cheap ones as the compound used in cheap shoes is pretty rubbish. I see you've already got replacement alloy wheels fitted so no need to change those. The calipers are Weinmann, probably 500 drop, and give reasonable performance providing they're well maintained (and you don't expect too much). The bike was designed for Weinmann brakes, so if you do replace them make sure the new calipers are aligned correctly with the rims and pivot corerctly.
There were 2 variations of the original 1986/7 Equipe model - the standard Equipe had steel rims with a gunmetal and white paint scheme; and the Super Equipe had Weinmann eyeletted alloy rims with a red and white paint scheme. Reasonable spec 12 speeds with high tensile steel frames - not very light and not very fast, but useful commuters.