If you travelled to the city that cost you one week. You should still be in the city right now.

If you travelled to the city that cost you one week. You should still be in the city right now.

The lieutenant pack adds a bit more diversity and balance to the game (imo), but doesn't add much content to the existing campaigns.
Basically it gives the OL a chance to play around Wildlander's Danger Sense and other discard mechanics by instead buying Plot Cards by purchasing Threat Tokens (or otherwise laying claim to them during an encounter). Thus giving the OL another place to spend his XP in a meaningful way as opposed to a card you may or may not draw, and it may or may not be discarded before you get to dish it out.
They usually add both to the hero's decisions and the OLs. If you are going to play the Road to Legend campaign however, I would absolutely not recommend a lieutenant pack for now.
 
If you are short on funds for buying more content, I would probably recommend a small box expansion, as it adds relics, monsters, heroes, classes and shop items, and you can incorporate the quests from there into the Shadow Rune or Heirs of Blood campaign, whichever you have (by rumor cards).
 
If you rather save up a bit I'd recommend Shadow of Nerekhall expansion (a big box one), I really enjoy that one as OL, and so far the heroes seem to enjoy it as well. 
 
I, personally, wouldn't bother with the Hero and Monster collections until you have possibly expanded the other parts of the game a bit, but each to their own.
 
Best of luck on your decision!