APT electricity question

[da13ear]

My g/f currently lives in an older (c. 1930s) bldg in Hell's Kitchen. Her apt is wired up with a circuit breaker, which has 6+ 20amp switches, but downstairs, in the basement, she has a single 15amp fuse (which will blow before the 20amp circuit breakers). Unfortunately this makes the circuit breakers useless, since the fuse will always blow first. What are the best means to look into a) whether she really only has 15amps available on the line, b) whether her line was wired incorrectly, and c) whether she needs more electricity? I understand that an electrician would be best, but they're too expensive to just evaluate the current scenario. Are there any NYC guidelines for minimum ampage in an apt? would her landlord have that info?
thx for any help that anyone can provide.
-Chris