can anybody please suggest me the rx required for
ImmersionRC 5.8Ghz Audio/Video Transmitter

You would need to pair it with an an immersion Rx since they operate on different frequencies than Boscam which is usually used. I think they would work with any 32 ch receivers tho. Anyways what you have to do is see if the Vrx supports these Frequencies: 5740, 5760, 5780, 5800, 5820, 5840, 5860MHz for your Vtx

Something like the Vrx below supports almost all the brands such as immersion/fatshark/boscam etc
http://www.hobbyking.com/hobbyking/store/__71091__ImmersionRC_UNO5800_v4_32ch_5_8GHz_A_V_Receiver_w_GS_Link_Dual_Output_NEW_Version_.html