STOP! Oil Pressure warning light

Hi all,

I'm hoping someone can help.

I have a 2003 VW Passat, V6 engine, which needed to be serviced about 2 weeks ago.

I drove the car to work yesterday and when I went to leave after work, the car would not start. The 'STOP! Oil Pressure' warning light has come on. I checked the oil level, which is really low.

I'm wondering if I should change the oil where the car is currently. Or should I simply top it up with new oil? Will any of these make the car start?

Thanks.