There are no converters for RDLC reports due to the significant difference in structure and expressions mechanism. If you want to switch to Telerik Reporting my recommendation is to keep the currently existing RDLC reports and start a new project for Telerik reports.
Details how to start with Telerik Reporting are available in this forum post
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Feedback Portal
and vote to affect the priority of the items