Getting google token string from play store page

I'm scraping this page: http://ift.tt/1iyv559 (need to be logged in google to view) I'ts the list of your purchased apps from the play store.

I want to see the next set of apps, which can be done by adding a start parameter: http://ift.tt/2uThUfu

start=199 works http://ift.tt/2uwLYee

But when you get to 200, it returns an error (429 Too Many Requests): http://ift.tt/2uTAPXl

So I tried replicating the button at the bottom labeled "more", watched the requests and its parameters.

It's passing this:

Request URL:http://ift.tt/2uxndhV
Request Method:POST

FORM DATA

start:80
ipf:1
xhr:1
token:xxxxxxxxxxxxxxxxxxxxxxxxxxx:0000000000000
pctok:(longString)

This returns a short html containing the next set of apps. Tried replicating this, but I don't know where to get the token and pctoken values. Tried searching in the cookies, other header files and the html with no success.

My question is where do I get these parameters? I can successfuly load the page on my code with proper cookies, but I cant replicate the "more" part.

So my question is where do I get the token and pctoken values?