brakes, dieseling, etc.

[brecchi]

i was driving my 300d on the garden state parkway when my oil pressure suddenly dropped. oil was everywhere and to make a long story short a mechanic off the parkway charged me 266 bucks to replace the oil line from the turbo. the problem is that now for some reason the brakes are extremely tough to press down and they feel really limited in their stopping power. also the car has begun dieseling and i have to press the manual stop lever inside the engine every time. what is the connection between all of these problems if any? i like working on my diesel but is this something a pro will need to check out? can anyone recommend a good mechanic in the d.c. area? i would also be happy to come over to someone's place one day and pay a reasonable amount to work these and some other nagging problems out for me. thanks