Your place of arrival in Romania will be most likely the Otopeni International Airport near Bucharest. When you show your passport and visa to the immigration officers, you may be asked why you have come to Romania and also whether you have enough money to cover your costs of living plus a return ticket. Before you go through customs you can exchange money at a counter in the luggage-collecting hall. The exchange rate is almost as good as you will get anywhere. The equivalent of about 100 USD will be enough to cover any expenses during the first few days.
Tickets are available at the ticket window there.
By train, it takes about 5 - 6 hrs. The Romanian climate is characterised by hot summers and cold winters. In winter there are many days with temperatures below freezing. You will need a warm winter coat and at least one woollen sweater. If possible, you should include these clothing items in your basic wardrobe.