Thirumal,
I did basically what Adam described. Unfortunately, I'm on a personal leave right now so I don't have my laptop handy but I'll describe what I can remember.
To start I separated the scripts into /scripts/ui and /scripts/services. You'll notice in Adam's sample, each test script is a class that inherits from a SaunterTestCase. We have our own TestCase layer that inherits from SaunterTestCase. So for services testing you'll probably want a ServiceTestCase class some where, which inherits SaunterTestCase but override the setup_method. This is where the browsers driver is created I believe, you don't need or want this for your test. Its up to you if you want this class to inherit SaunterTestCase. I remember we did to use the soft asserts. If you don't care about that, you can use the native assertions. For each script, I'd create a service object, i.e. UserService, and do your thing. In each service object I made use of the request library but feel free to use urllib if you like. Doing it this way, it's easy to change later.
That's pretty much it. Let me know if you have any questions.