What ASIC are your planning on buying?
If you buy antminer you might not need to use the RPI unless you plan on hosting a proxy connection or running your own small node with it.
Most miners come with API and GUI for setting up.
AS i mentioned I have completely no idea about how mining thing works.
I need suggestions , If i start mining what hardware should I go for.
Please through some help if you are good at mining.
I am looking for some decent income with mining , if otherwise possible.
Read about mining. Google is your friend. No one has been able to mine Bitcoin without using super specialized-hardware for nearly 4 years. You can buy a R-Pi for $35.00 If it could be used to profitably do
anything, you would not be able to find them for sale, except on Ebay for 3-4x retail.