Plateau

I think I may have hit my first plateau.  I've only lost 1.5kg since I started this blog, but from my heaviest weight, and since I've started seriously trying to lose weight and I've lost 15lbs. My exercise routine has switched to walking from work out tapes.  I've been bouncing between 98.5 and 98.2kg for the past few days.  I have also been having some serious back pain, which I believe is related to my lack of necessary stretching, but that's a post for another day.  So, as it's Monday it's supposed to be my first workout day of the week since Saturday and Sunday are my off days.  I couldn't do it this morning, just walking makes my back hurt.  I've been spending my day cleaning and intermittently doing back stretches for 10 minutes.  I'm hoping to be able to do yoga tomorrow on top of my walk and have that make things better.

So, my question is what is the best way to get past a platuea? My first weight loss goal is 4 weeks away and that means I need to lose on average 1.3kg a week to get there.  It's important to me to meet this first goal.  What can I do to get there?