First be sure this is not just due to her having just drunk. If this is due to a nasal discharge you are right to be concerned and unfortunately this is all too common a story. Moving birds is stressful for them and this can cause latent infections to break out.
Mycoplasmosis is one such and is known as stress disease. It attacks their upper respiratory system producing the sort of 'cold' symptoms you describe. The risk is that the mucus lining of the respiratory tract is damaged which allows other infections to gain entry to the bird and which can be far more serious.
The best option would be to contact the supplier immediately as most will give some sort of guarentee of health. You will obviously compromise this if you start to treat it. (For the benefit of any other newcomer reading this, you should always ask this question along with others aimed at finding out how they ensure healthy stock. If they don't give satisfactory responses walk away there's plenty who will. Remember you should be able to have a completely no stress purchase not immediately have a problem). Your other options are isolate it and keep it under observation and hope it clears up without complication or give it some antibiotics as soon as possible to control it before other infections can occur. If you get an antibiotic I'd treat the lot by adding it to their water.
To get antibiotics you will have to see a vet. Tylan or Baytril are the usual antibiotics which are quickly effective. You can always contact your supplier and tell them what has happened and either change the bird or they may have a/bs to treat her. If it's not complicated with other infections all well and good but generally birds which do this carry the bacteria and further outbreaks may recur under the stress of starting to lay or moulting, or heat stress. If you keep the bird that's a risk you take.
Best of luck
HF