Is There a Cafe in Nintendogs? No

There is no café in any Nintendogs game (DS, + Cats on 3DS).

Actual Social/Outing Locations

• Dog Park: Walk → Meet neighbor dogs → Play / Bark mode (local wireless).
• Gym / Agility Trial: Practice disc, lure, obedience for competitions.
• Shopping: BARC (supplies), Interior (furniture), Accessory (hats, collars).
• Vet Clinic: Checkups, vaccinations (only in + Cats).
• Hotel (Nintendogs + Cats): Leave dog for streetpass visits.

Maybe you're thinking of Animal Crossing (café: Roost / Brewster) or Tomodachi Life (café area)?