German Visit decided/Undecided

Hi Members,

    i'm santhosh from india. I m planning to do my PhD studies in germany and also i'm trying for german universities to get the admissions too. But it seems the feasibility of getting a PhD admission in German universities is a little bit tough. So, right now i'm  planning for getting a job in germany with the intention of doing a part time PhD as well in Germany. My questions is, which visa should i apply(Tourist/residence permit/work permit) and which visa would be suitable for me??. I m from computer science background and how about the job opportunities there?.

Please guide me through!. Any help in words?

My Education Qualifications:

Post graduate Degree Holder.
Learning German

Thanks and Regards,
Santhosh.L