Wife is told needs more dairy fats.. looking for alternatives

Hello, my wife and I just had oue 3rd son who is now almost two weeks old. He was 6-3 at birth and has been 5-10 at the last two check-ups. Doctor wants to check again in five days and says if he has not gained we would need to supplement (she is breast-feeding by the way). The baby eats all the time it seems and is very healthy otherwise so doctor thinks her milk doesn't have enough fat. This is our first totally natural and vaccine-free baby (much to our doctors dismay).

But the doctor says my wife needs to start getting dairy fat. We have been pretty much a dairy-free family besides some raw cow cheese and goats cheese from time to time. Can anyone suggest other fats we can use and also point to links of good sources I can read more on the matter? I know that avacado's are good but some other GOOD sources of fats would be nice as well.

Thanks!