Bonsai problem... how to hold it? i have a Bonsai plant i hold broght it from a humid...

i have a Bonsai plant i hold broght it from a humid place last year to my city that enjoy dry and cold weather.my Bonsai was righteous but in later 5 days it has gon leavesless and is going to be died i guess.i dont know if its the problem of watering,its soil or the weather.please help me.how much watering does it obligation? when i should change its soil? or repoting it? within summer i water it everyday but contained by winter every other day or every 2days.
Answers:    Any warning you receive is worthless unless the species is known. You are make the acquaintance of to send a photo to me at:
wchoat@american-bonsai.com . After we identify the species, I'll report you what to do. If you don't have a path to send a photo, look at the bonsai (100's of species are used for bonsai) on my site:
http://www.american-bonsai.com and see if you can find one similar to yours. Also read the Bonsai Care page on my site, it will help.
dont river it, my partner got one that be near release and now it looks amazing, iif the soil is dry after soak it for about 10mins contained by a bowl ofter water, than only just sit it on a humidity tray, and keep that packed, this will keep your bonsai looking majestic....you can buy one from the link below...you dont carry the stones with it, and we dont use them on ours anyway, but it lately stops the pot from sitting in the wet and prevents the soiling drinking in the river from below......good luck next to it and i hope it works out for you.......we have 2 trees within a tray like this, and as i said one of them be dead, no leaves, no nought, now, its twice as big as the other tree, haha, so these trays do work