Volkswagen Repair: vw beetle 1600 power loss, fuel system components, ethanol gas

Question
my 1600 beetle used to run so ewll it was so fast and zippy.
although very heavy on petrol.now it has absolutely no power.the other day it died in first gear.and would not start,but after a minute or so was running again.
so i am not sure what is causing it to have no power.
i thought maybe the air filter as it looks to be very clogged.
i hope that can make a difference,otherwise i do have quite a bad oil leak at the bottem of the engin.
my main concern now really is the loss of power and the heavy fuel consumption.
i love my little beetle and i would greatly appreciate any advice.
thank you

Answer
Richard,
  I know very little about VW gas engines, my area of knowledge revolves around 70' and mid-80's vintage diesel engines for the Rabbit model.  However, I should mention that a clogged air filter will cause loss of fuel economy as well as (in extreme cases) a noticeable lack of power.  If you are living in an area cursed with ethanol/gas formulations at or above 10%, your older engine will experience less power and decreased fuel economy (as well as potential damage to some fuel system components).  Also, you might change the oil and use multi-grade oil recommended for that engine (ofttimes, engines with severe oil leaks are merely topped off, rather than given regular oil changes).  Hope this helps.  Jerry