To the relative "newbies" posting on this thread.... as Kristine points out, this is a very very old thread so it is unlikely that most of the original posters will be around to respond to your questions. (If you look at the top of the first post in a thread, you can see how old it is.)
With regard to the original question: how long it takes to lose 65 to 70 pounds - or any amount for that matter - is HIGHLY individual. It depends on your starting weight, how stringent you're willing to be in cutting carbs (and perhaps calories), your gender, your age, YOUR basic metabolic rate, and just how often the WHOOSH fairy happens to be in your neighborhood.
Seriously, weight loss is so individualistic that comparing the rate at which you lose weight to other people's results is an exercise in frustration! There will always be others who lose faster than you do, as well as others who lose more slowly.
When one is desperate to lose weight, there is a tendency to notice those who are losing more rapidly - and assume that you're doing something wrong because you're not losing as fast as they are. I have a feeling that comparing ourselves negatively to others results in more people giving up and quitting than just about any other factor.
We share the details of our journeys here NOT for comparison purposes but so that we can encourage each other, celebrate each other's victories over the scale, and learn from each other about the kinds of "tweaks" that worked for others and that just MIGHT work for us as well.
Commit to low carbing, pay attention to what works best for you, and then STICK WITH YOUR PROGRAM and you will lose weight. It may come off quickly. It may come off at a snail's pace. More likely - sometimes you'll lose weight very quickly and other times, while eating exactly the same way, you'll hit a plateau and go for weeks or months without losing a pound. And then suddenly, you'll start losing again. Hence the references you'll find sprinkled throughout this forum to the "WHOOSH fairy."
While losing weight quickly is nice in that it tends to keep us motivated, slower weight loss is probably healthier. 1) It gives your skin time to adjust so you don't wind up with nearly as much saggy baggy wrinkly skin. 2) You have more time to get used to living in a slimmer body. 3) As you lose weight and feel more energetic, you are likely to FEEL like being more active and with increasing activity, you won't lose as much muscle mass. 4) You don't have to cut food intake to starvation levels, instead you adjust your intake slowly so that by the time you reach your goal weight, you can maintain that level just by continuing to eat EXACTLY the same way you have been for weeks/months by that point.