Place vegetable oil in a saucepan over medium heat, and cook and stir the onion, leek, celery, red bell pepper, and garlic until the onion is translucent, about 5 minutes.
Pour in the chicken stock, bring to a boil, and stir in the carrot, tomatoes, couscous, raisins, and currants. Season with curry powder, turmeric, salt, and black pepper; bring the mixture back to a boil. Reduce heat to low, cover the pan, and allow to cook for 5 minutes.
Remove from heat.
Let the couscous stand covered for 5 minutes, and fluff with a fork.