Help with code(SearchCursor) - urgent

Hello everybody,

I'm a student of Geomatics in Portugal and since I'm new with the python language I'm with some problems with my code.
I need to finish it as soon as possible to be able to do my internship and maybe some of you could help me - unfortunately I dont have anybody in Portugal to help me with that-,
the "question" that I need to answer is really easy for those who know how to use properly the python language.

a) Public transport accessibility

Data: vectorial themes edificios.shp (buildings.shp) and paragens.shp (bus stops.shp).

Question: For each building how many urban careers (bus carrers) can be accessed within R
meters from its centroid?

Present the results in an accessibility attribute to create the theme edificios.shp

I know that it is quite simple and the main function is the SearchCursor...

Please if you can help me mail me(and/or skype) to juju_18zw@hotmail.com
I can send you the 2 shape files and explain you better the question.

Hope to hear from you soon,

Julia