Let me tell you CRM (Customer relationship management) Isn't a narrow subject that you can I think create a whole by yourself.
There are
many CRM products[
^] available in Market and they are also heavily customizable to make it fitted for your organisation.
The few of them are
1)
Microsoft Dynamics CRM[
^]
2)
Sage CRM[
^]
3)
SAP[
^]
4)
Sales Force CRM[
^]
I would suggest you to use MS CRM as it's heavily customizable with everything you need if cost doesn't matter to your organization or other side you can also have SageCRM for lower cost.