Router for Cherrinet

Hi Guys/Admin,

Looks like I've come back here after 3 years..(admin-thanks for guiding me last time towards reliance). However, now I've taken Cherrinet (Upto 200mbps plan) but I am facing quite a few issues.
1) my pc supports only 100mbps (so I've ordered for a gigabit port)
2) the Netgear n600 does not support gigabit wired & wifi and hence I am eligible for a speed upto 100mbps.
3) the range is worse than my D-Link 2750u Adsl router (n300) It cuts the signal terribly even with one wall in between let alone other parts of the house

I could really use your guidance on which router to choose as I can still return and make a change. Do I get a netgear ac1200 router that supports gigabit wired&wifi (skeptical with the range quality of netgear) or shall I choose a dlink router (if so which one or rather which router would you suggest) and will the port help support the 200 Mbps plan or are the technical guys just passing the buck as I am receiving only 12-70mbps (70 being rare) on the lan connection?