Yes, the species of the baby will be based off of the female that you bred, unless you bred a male with a Ditto. In that case, it'll be based off the male.
As for how long it takes to get an Egg, that depends on a value called Breeding Rate. Every 256 steps you take, the game randomly decides if you get an Egg. You have a higher chance of getting an Egg if you're breeding two of the same species together and/or if they have different trainer IDs. Most likely you're breeding two Pokemon that you yourself caught, which means they have your trainer ID. This is what the individual rates are:
Same species, different ID numbers - Chance of Egg is 69.3%. The old man says: "The two seem to get along very well."
Same species, same ID numbers - Chance of Egg is 49.5%. The old man says: "The two seem to get along."
Different species, different ID numbers - Chance of Egg is 49.5%. The old man says: "The two seem to get along."
Different species, same ID numbers - Chance of Egg is 19.8%. The old man says: "The two don't seem to like each other."
If two incompatible Pokemon are used - Chance of Egg is 0%. The old man says: "The two prefer to play with other Pokemon than each other."
So as long as you put two Pokemon in there that are compatible, you will eventually get an Egg. If you have Pokemon that were traded to you from other games, you improve your chances greatly. Just ride around on your Bike in front of the Daycare. When the old man has an Egg for you, he'll call out to you as you pass by him.
Hope this helps :)
