ISO 9001:2008 and ISO/IEC 20000

I work for a company dedicated to financial matters, and the IT department is the backbone for all transactions. The IT department is particularly interested in obtaining an ISO certification; however, not the rest of departments of the institution. We want know 1) if the ISO / IEC 20000 is the right certification for IT division or should we aim for the ISO 90001:2008; 2) if within the ISO /IEC 20000 we must certify in its entirety from part 1 to part 11. 3) Is the 20000 toolkit offered by your company includes all 20000 parts? and last does your company offers audit certification on ISO /IEC 20000? I contacted Bureau de Veritas but they do not offer this ISO 20000 certification or training.