Mystogan

Originally Posted by Big_King

Yes, that is correct. In order to play Going Rogue restricted content, you will need to have a GR retail code applied to your account.

For your earlier question, see my link to Game Cards on the wiki. You can upgrade your account to full status using a "Game Card", but that is different than a "Time Card" (typically a little more expensive and may only be able to be applied once to an account). Depending on what you can get your hands on, I would guess your best two options are:
1 - Apply "Game Card" to upgrade from Trial to Full. This gives you 30 days of play time.
2 - Apply a Going Rogue Expansion retail code to give you access to GR.
3 - Add more time using a credit card or "Time Cards".
OR
1 - Apply a Going Rogue Complete Collection retail code. This will upgrade your account from Trial to Full, give you 30 days of game time, and give you access to GR.
2 - Add more time using a credit card or "Time Cards".

Originally Posted by The_Spad_EU

You need to purchase a retail copy of Going Rogue, but it's available for ~£3 more than a 1 month timecard and comes with 1 month of playtime, so it's really cheap.

If you already have the game downloaded for the trial account then you can continue using it, otherwise you can just download the launcher and it will download the whole game for you - there's no need to "install" from retail media in order to play.

Originally Posted by Big_King

I do not believe you can apply a time card directly to a trial account. First, you must apply a retail version of the game to your account to upgrade it to a fully functional account. Which version you purchase to upgrade it will dictate whether you can access Going Rogue features. If it's a GR retail version (e.g. Complete Collection), then you can access it. If you buy a CoH or CoV version (e.g. Good Vs Evil or Architect Edition), then you can not. You can then apply time cards to your account to extend your subscription. Note that most retail versions come with 30 days of game time included.
See the Wiki for the different versions.

To my knowledge, the download is available publicly and you do not need an active account to install the game, just to log in and play it.

PS - Perhaps you are referring to a Game Card, which it appears functions similarly to a retail edition, but looks like a time card. If so, this will NOT get you access to GR.