Wow princess, as bad as that is, it could have been a lot worse.
The expander bolts are great for fixing into concrete as Snowy has pointed out.
You will need a masonry drill bit and a hammer drill.
Oh yeah and ear muffs because it so damn loud drilling into concrete.
The other option is to make a support frame out of timber where the uprights support the top beam.
Full proof. No way will that top beam fall, ever this way.
Here's a diagram of what I mean
You could probably stick with your liquid nails for this and all you need is 3 cut to size lengths of say 70 x 35mm pine.
Measure up and get the dude at the hardware store to cut it for you.
It'll be cheap and full proof.
All the best.
...Can we stop saying shit happens in threes!
Keep saying that and you'll speak shit it into being!