Your gear is too low to enter on normal mode? When I hit lvl 80 I did Forge of Souls which is a requirement to get into Pit of Saron, and then just did the instance over and over until I got 5 weapons. You only have to kill 3 mobs before you get to the first boss, so you'll get them all 212 dps weapons fast.

This is for sure the best way to gear up