Easy...Kiosk at the top of the escalator to platform 1 & 2 has them (near the big waterwall underground thing in the train station). They have strawberry and blue.
If you want something closer to 'red' cordial then the lolly shop in the HB has them. They have three flavours - strawberry, blue and red 'fruit'.
I can also recommend buying gatorade or powerade or some other 'sports' drink, freeze them.
I had major crushed ice cravings during pregnancy - just don't do what I did and crunch whole ice...major dentist issue