Welcome to the forum.
I can really understand the imprecise nature of your 10 to 15 pound target... Sometimes we do not really know where we want to settle until we get there... We may strive to wear a certain size of clothing or to feel that we look "right"... I know the weight that I settled at in my big weight loss project - but the world has moved on from there... in addition to gaining some fat since then I have also gained muscle and know that I look thinner and am wearing smaller clothes compared to the last time when I had my exact current weight...
I really do not know what weight I will end up settling at - and can therefore fully understand your uncertainty.
Since you are so close to your stated target - it may be a level of toning that will appeal to you more than anything - so maybe you would prefer a target stated in inches rather than pounds... Alternatively a certain percent of body fat... Maybe your journey there would be better achieved in completed exercise levels done... I know lots of people that swear by set programs - things like 30 day shred and insanity... Maybe the determination to complete such a program could give you motivation to get to where you want to be...
I know that I only feel good about myself if I achieve a certain amount of exercise every day.
As far as motivation goes - I find nothing so motivating as wearing a fresh outfit that fits me well at my current weight - even though I would like to lose more... I find that I can do this all the time - by buying clothes at charity shop... I buy an outfit for the price of a magazine and a charity benefits... When I lose some more weight - I can hand bigger clothes in and the charity benefits again... Good causes benefit and I feel good about the way that I look. People can feel awkward about buying clothes at such shops - but there really are brilliant bargains to be got there if you are selective... some of the clothes on offer are brand new - I have bought plenty of clothes which still had their original price tags in... No-one knows where you bought it or how much you have paid unless you tell them... Over the last three weeks two people have complemented me on items of clothing that I have bought and asked where I got them as they would like something similar... both items have been charity shop bargains...
However you choose to get to where you want to be - I wish you luck in getting there...
I suggest that you read the following thread - it may help you settle in and make friends
http://weight-loss.fitness.com/threads/57955-My-advice-to-newcomers
Good luck with your project.