Despite the bad press Tottenham has had in the past, It is fine. It is in the middle of being regenerated. Not much to do as far as shopping goes as it is full of little corner shops - some of which will have gone since I lived there. There is, of course, the new stadium which I have yet to see. Wherever your hotel is, take a bus to Seven Sisters tube station and from there, it is about 15 minutes by tube to Oxford Circus. If going back to the hotel in the evening, just remember, the majority of people are doing just as you are and going back home. I lived there for over 12 years and traveled late at night home on a regular basis. I never once felt frightened, was never mugged, my house was never burgled.
Just do the sensible things like keeping to well lit streets, don't have your phone out as you leave the tube and keep valuables hidden - the same as you would do in the centre of London.
If you are at the Premier Inn, Tottenham Hale, then there is a small shopping area near Tottenham Hale station. If you are nearer Tottenham Hale, then the Victoria Line passes through, so you could get the tube there. Don't panic. It might not be central London, but no doubt you are getting a cheaper hotel and the area is not that bad.