I knwo a popular Indian restaurant called Ganges Indian Resterant, which is located about 3kms away from the hotel. You could take a taxi to arrive there in 10 minutes. The restaurant address is: 海淀区成府路160号三才堂写字楼1楼

Of course, one day is enough to visit the Great Wall. I think you could refer to this website's suggestion: https://www.travelchinaguide.com/package/beijing-one-day-tours.htm