I would like to consume all the application performance monitoring related data provided by new relic in the form of REST API's so that i can show it in our own dashboard instead of seeing it in New Relic dashboard. Is there REST API's available for this?
The documentation for the REST API is available online.
But think twice about obtaining "...all the application performance monitoring related data provided by new relic..." There is a huge amount of data available and you most likely do not need it all. If you attempt to pull out too much you run the risk of encountering 429 errors (Overload Protection) and filling your local disk space.
Decide what you want and the longest period you can stand to collect the data at and request just what you need.