help with wi fi connection

Hi, i have a macbook and have mac os x. i dont know much about computers in general, but really need help getting connected to the internet. im from the usa, but now living in spain in an apartment. my apartment owner has a wi fi connection, and she uses the internet perfectly. today she gave me the password, which worked, and it says that i have a perfect connection but it wont let me go onto the internet and browse or use skype or anything. im really confused, and would really appreciate any help. her company is called jazztel. and the password is a WEP one. i´ve been using my laptop all over europe and have never had a problem getting wireless and onto the internet. any suggestions...thanks!