Customized Customer Relationship Management Database (Custom CRM) - repost

Our business (junk car purchasing) needs a user friendly database to allow our sales department to track incoming calls, offers made to customers, purchases made, etc. Our sales department constantly takes incoming calls and we need a centralized database with all information on all calls and tow assignments. Instead of using a system like Salesforce, we'd like a simple custom built CRM that we will be able to modify in the future as we expand our company. All source code will need to be produced, visible and easily modifiable by our on-site developers. 1) We will need an API connection written in XML to monitor changes in the VOIP system, and register active phone calls for each of our sales representatives. This will allow our representatives to select an active call and either associate it with a new offer, or look up any existing offers associated with that phone number. 2) This database will need to allow the sales representatives to enter an offer for each new call with the Year, Make, and Model of the car, our internal code for the tow company being used, a confirmation number received for the tow, Payout (amount to be paid to the customer), customer name and contact information (Phone number(s), Address), VIN #, projected profit (how much will be paid to us after the tower pays the customer) and any additional notes. The system will auto-populate the Job ID number which will include a predetermined company code and the number of the job. For example if the car was picked up by "NWR" and it was the 122nd tow assigned to "NWR" the Job ID will appear as NWR000122. Each tow company will start from 000001. 3) Once an assignment is created, we'll want to create template emails, incorporating the fields from our assignment entry forms. We'll access these in text format, so that our employees can copy them into an email and send them out. Within the database, every quote given, or tow assignment set up will need to be assigned to the representative who is logged in, and any notes will need to be recorded relative to the login of the representative. 4) Once the data has been entered any quote or pickup assignment can be pulled up. The junk staff can pull up any profile by searching for the name of the client or VIN or their phone number (which is a required field.) 5) We'll need to be able to administer the system to add new users, and new towers 6) There will be two or three reports required, and we'll need to export information from the tables for this purpose, either in CSV or Excel format. More detailed specifications and wire frames will be provided on developer acceptance, including documentation of the API connection for VOIP.