About a month ago I bought my first bonsai - a Serissa (little did I know how difficult this species is to look after). It's been growing relatively well, but has been on a very slow decline since purchase. There has been no obvious leaf growth or new stems within this month, and the tree has gone through periods of browning leaves etc before bouncing back, until recently.
I keep my tree indoors (as my uni room doesn't have a balcony) underneath a window. It never receives direct sunlight in that spot, except weekends when I move it to the sunny patch on the floor. I have a chopstick inserted into the soil to check moistness and I have been watering and misting it accordingly. I have had training wire on the tree since the beginning, but recently I decided to take it off as it began looking sick. Taking off the wire completely moved the entire plant in the soil, so I repotted it into the same soil in a better position (the soil is from a Bonsai Potting Mix from Bunnings) about a week ago... but since then the leaves have started wilting and turning brown! It's only a matter of days now before the tree completely dies, so I'm desperate for help! I keep it in a small tray and water NEVER touches the roots, so root rot shouldn't be an issue and I can't see any bugs or pests on the tree.
This is my poor tree:
http://oi61.tinypic.com/9qw6zo.jpg
and here's a closer look at the leaves:
http://oi60.tinypic.com/iqjvh1.jpg
Someone please help!!

EDIT: Two weeks ago I moved the tree five hours up the Queensland coast but it seemed to survive the journey well enough, I don't think it's related to that at all!