The hose is just for overflow. Tuck it under the air box and don't worry about it.
The radiators are known for cracking. Mileage or age doesn't seem to matter it's kinda random.It's a fairly easy job if your mechanically inclined or take it to your favorite mechanic.
You can mail order a stock replacement thru some place like RockAuto or a local radiator shop.There are a few all aluminum after market ones available thru company's like Ron Davis Radiators but carry a higher price.
Coolant loss seems excessive for that spot you showed.If you can't find the leak You may need to have a pressure test done on the cooling system