You can easily update your php settings on your Managed WordPress account from within the nvArea.
Once you login you can go to Hosting Services, Manage Hosting.
Once there, click on your hosting account on the center of the page.
Once into your account, click on Manage Instances, and then hit the green manage button to the right of the domain name.
You will then be presented with a series of tabs, one of which is PHP Settings. This will allow you to update a series of PHP options including the version, max_filesize upload size, and max_postsize.