Gearbox selection & oil leak?

Hi there, I have a 1998 Ford Escort GLX TD wagon, It's done 190kms and been serviced on a regular basis. About a week ago whilst slowing down for lights, I could not engage gears with out a little bit of a fight! I managed to get it home and now it's parked up. I've never had any issues with it before, however I noticed 3 weeks before said incident, a small leak under drivers side (diesel oil?) Upon inspection, it seems to be weeping out of the "pump wheel looking thing" next to the oil filter. Could this be a cause of gearbox de selection? or a seperate 'need to fix' issue?

I've read on here about a clutch adjuster under pedal!
It does take a little pounding as they are slug's to get off the line, and also it does seem a little spongy now??
It's been a fantastic little wagon, and boggies along well on the motorway, I'm planning on having her for a while.

all sugestions and advise would be welcomed. thanks