The strength of the company does not matter for attaining any level of CMMI. The only thing that matters is that your company should follow all the practices specified by the CMMI model.
The first step to attain any CMMI Level is to create a Quality Management System (QMS). QMS is basically a set of documents which contains the details about the the process and procedures that happens in your company.
Usually companies would hire a consultant to do these kind of activities, however with certain knowledge of CMMI companies can create these set of documents.
Once all these documents are created, then these are compared with the CMMI Model, to find out the gaps in the QMS of the company. This activity is called as GAP ANALYSIS.
Based on the outcome of the Gap Analysis the QMS is then restructured, redesigned and re documented. Gap Analysis will continue till no Gaps are identified in the QMS.
After the completion of the Gap Analysis, then the company can go for certification for CMMI.