1998 Renault Megane • 195,000 miles

Hi, I have recently driven quite a distance with my car, and about a week ago, it started giving me this problem.
What happens, is that while driving, the engine would feel like a car thats running out of petrol, it does not do this constantly and only after driving about 40km's or so.
when saying it does not do it constantly, I mean. It would have normal power for say 10 seconds, and then feel like its cutting out for 5 seconds or so.
When it starts doing that. If I press hard on the accelerator, it starts picking up revs, but then it drops, feeling like its not getting enough fuel through.
I see that I have a small fuel leak on the pipe going into the injectors. Would that be a cause of this problem?
Furthermore, I had a listen to the fuel pump(intank) itself, and it does not sound like it is straining.

A few people have told me that its the pump, but im trying to avoid replacing it until last, as it is extremely expensive where I stay.
February 2, 2012.

Check the fuel pressure with a gauge if its within specifications and repair the leak-you're losing fuel pressure

Feb 2, 2012.