You'll need to take a short taxi ride almost anywhere to get what you want.
Closest to your hotel, my recommendations are:
1. Cane Rosso. Aside from serving the best pizza in Dallas,
they offer many vegetarian options.
2. Samar. Excellent, Indian and Middle Eastern food with some interesting vegetarian options.
3. Spiral Diner. Very good, 100% vegetarian food.
4. Lemongrass. Delicious Vietnamese food served in a very comfortable "white tablecloth" setting with excellent service.
Any restaurant in Dallas will be happy to call a taxi to take you back to your hotel.