How To Upgrade Your Membership:
First click here to open the upgrade page, then follow these steps: 
(Mobile Users: Keep both windows open so that you can read here)
Step 1:
Scroll down to the prices and click on the blue link on the price.
Like the picture shows:
Prices
Then select the one you now want. 
This is not an automated subscription which means You have full control
Make sure you have the right membership selected.
From Only $4.04 Per Month
$97 / 24 months =  $4.04 per month
As you might see, the longer the cheaper.
Sometimes it looks like this Instead of the above:
Step 2: Make sure you have the right Gateway selected.
Make sure right gateway
Step 3: 
Click The Buy Button it looks like this
For more help see also