Dear Charlene,
Let me start by saying congratulation!! I too am in the same boat. I have recently given birth to my second child (he's now four months old) and have a toddler to take care of as well. If you are breast feeding, DO NOT be in a hurry to lose all the weight. I was and I regret it. If you are not breast feeding, then my best advice is this (if possible): try to exercise first thing in the morning, maybe after the morning feeding. With the added challenge of sleep deprivation, later on in the day you may not be as motivated. Concentrate on building up your core strength as you will need it for carrying the car seat, diaper bags, etc, as well as for a "baby bjorn" or similar sling.
Also I found my upper body strength needed some work as well since I couldn't do push up while pregnant (or lying bench presses, etc.)
As far as where I am at four months later, I can tell you that I am still fitting in my size four's (thank god!) at the age of 34. Genetically, I tend to have a ripped ab region. Even now you can count the abs but there is still a lot of excess skin that just isn't going away with the second child. A piece of advice, don't take your measurements! In a nutshell, my regimen is that I am really hitting weights.
The routine that I use for when I have limited time is as follows:
1 hr. cardio (Imax 2)- M
1 hr. muscle endurance - T
1 hr. lower intensity cardio/steady state (rythmic step or a Christi Taylor workout)
1 hr. wts such as Power hour or MIS
day off
1 hr. cardio + wts.
1 hr. pyr lower body
1 hr. cardio - boot camp
1 hr. pyr upper body
day off
The real challenge is not eating too much especially if you are breast feeding (it's only 500 extra per day), or if you don't get time for the workouts then you will need to scale back calories, or not eating when you are tired and want a pick me up.
Good luck and best wishes for you and your little one!