You really should get the new dlc package. You get far more game. The problem with only vanilla Destiny is that they actually removed half the game when they brought out The Rise of Iron. You can't run heroic strikes, nightfalls, iron banner, trials (I know, you needed House of Wolves for this in the first place, but even that got removed), not even sure if normal crucible is open to you. When I started a new character I noticed that more than half the missions are no longer part of the story mode too. The new dlc will give you access to everything including 2 new patrol areas. I will say this. Don't use the level boosters. It might bring your level up to 20 but you still need to rank up your subclasses. In other words you may be level 20 but you still won't be able to throw a grenade or double jump. At least the story mode allows you to get rep to boost this.

You have to, unfortunately buy destiny again, the best thing to do is to sell your other copy