How I can be better?

I have 70 km per week. Is it enough for maraton?

depends how you're training... if you're running to fast or slow your wasting your time.

So usually i have a week like this: 35 km - pace 5 min/km, 18 km - min/km 10 km - 4 min/km 5 km - 3:15 min/km, 2 km - 3 min/km, 2 days for relax

ok but hard to help still - do you want to be faster im guessing so?

first you need to reflect on your health, are you healthy or is what you're doing now too much for you ie are you tired, get colds often, or injured often? if so you need to cut back the training and you will find you get better from doing that, simply because your body will be healthier. 

I have usually got such plan of trainings:

Mo: rest

Tu: (4 km pace 4:50)+(5x800m pace 3:15, jogging between 2,5min)+(3 km pace 5:00) or (4 km pace 4:50)+(6km pace 3:35)+(3 km pace 5:00)

We: 10 km (pace 5:00)

Th: 15 km (pace 4:30)

Fr: rest

Sa: (4 km pace 4:50)+(8x200m pace 2:35, jogging between 250m)+(3 km pace 5:00) or (4 km pace 4:50)+(10x100m for 15 sec every 100, jogging while pulse