SAP Basis certification

Hi,

I have 3 years of experience in SAP Basis. I want to go for the first level of certification in SAP Basis administration. I searched for guide lines but not got any clear picture.

please anybody help me in :

1. The basis certification on SAP Basis certification and its cost.

2. The documentation which i have to go through. As of now I have TADM10 and TADM12 documents. Which other documents i have to go through.