Shadow of Revan content. Forever included in 2 month subscription?

Hi,

I pre-purchased SWTOR and enjoyed playing it at the beginning, until I moved to another country, where the lag/ping is terrible and renders the multi player content unplayable. So I let my subscription end.

Later the game became F2P and now I play it again in order to get to at least enjoy the story.

I've just reached level 50.99 on Alderan. I would prefer to continue to  level up, whilst still playing the main story. So I seem to have 2 options:

1. Buying The Shadow of Revan for 20 USD or like 35 EURO (since I've only got a credit card and paypal account there).

2. Starting a new subcription. Maybe taking 2 months (paying once option). I don't see the point of having a continuous subcription, if I can't play all the game contents (ping in the evening went once over 100'000ms). So MP content is useless to me.

I plan to try the 2 month subcription later on, since I'm curious about fallen empire and I would really like to increase my storage areas. I might also want to do some crafting then and for that my 350'000 credits max is not cool. But for now It's probably just a waste. 

My question(s):

What should I do? Will I get permanent access to Shadow of Revan and the hutt cartel, if I take the one time 2 month subscription or can I just play it for 2 months and then no longer for a new character for example? Like I said, I still play the main story with my new character. This will still take some time, I suppose. I'm a slow player. I like to explore etc. If I get unlimited (time) access to Shadow of Revan and the hutt cartel story line, I'll take the 2 month subscription. Otherwise I would have to buy it seperately. And then later the subscription for fallen empire.