Can't get the report I want leads->sales

Can't get the report I want leads->sales

This seems like a simple one to get, but zoho support is no help or say it can't be done.

Here is what I want: I want to know how many leads a sales rep got, and how many of them they sold, in a month.

Here is our process: Lead comes in to CRM assigned to manager, who then transfers ownership to appropriate sales rep. Sales rep turns it into a potential, then eventually a potential "sold".

I can't even see how many leads a rep got last month, because they turn into potentials so now the leads by ownership is empty.