Hi, if you can clarify as to what your present setup is and what exactly you are trying to improve. If it's just internet radio I am sure you have lot of other options. Further NAD C427 seems to be just a tuner with no internet radio provision.Suggest to drop it anyway
In case your existing setup is modest then the Marantz AVR should suit you well. Better give more details so that members can guide.
On another note if you are staying in Delhi you should have access to good number of FM channels. We're u not able to source a standalone tuner. You should get a used one for 2/3k in good condition and the difference would be significantly better if you have a half decent stereo setup. Investing in a new tuner doesnt make much sense now a days. You can try for Norge tuner also if you need a new one. Excellent quality with good sensitivity.