Fermentation Stuck at 1.020

[2nd-Gen_Brewer]

Hi,

This is my third brew, so I'm relatively new at this. My first brew turned out wonderfully, my second was done using an old mix, so ended up contaminated.

This brew is using the same recipe as the first:
1 tin Morgans Blue Mountains Lager
500g dark dried malt
500g dextrose
250g powdered corn syrup

This time, around 5 days into the fermenting, the brew's temperature dropped to 12^C. This got the brew stuck at 1.020 for around 6 days.

On the 16th October, I phoned the brewery that I bought the ingredients from, and they suggested to re-pitch the yeast, since it had already been stuck for a few days. I did as he asked: 500mL luke warm water, 1-2TBS sugar, yeast, stir, set aside for an hour, then pour over the top but don't stir in.

It's now the 22nd October, and the brew is still stuck at 1.020.That makes it around 19 days brewing; 12 days stuck at 1.020. The temp has been a constant 20 - 22^C since the 16th October. (I put a waterbed heater pad around the wort.)

Is my brew still fine? Should I bottle it now, or does it need to be thrown away? Is there anything else I could try to bump it into gear?
The last brew with the same recipe ended with a hydrometer reading of 1.010.

 

[2nd-Gen_Brewer]

Quick update:

Shortly after I posted this, I phoned a brew supply shop who asked me if I stirred the yeast through when I re-pitched. I said no, because I wasn't advised to. She said get an aerater wand, stir it all up and test again in the morning.
Well, it's morning now, I've just taken a reading, it's gone from 1.018 to 1.016! It's still very cloudy, so I'll take another reading in 2 days.