Hey Littlewing
The anger issue has allready landed me with a fracture in my hand and the loss of a gf (clocked one of her friends), so I know exactly where you are coming from. As for the impatience...just talk to any of my former co-workers and theyle attes to me being a "kind-hearted, short tempered, devil of an angel".
Rage and impatience is almost a stereotypical hallmark of someone with Bipolar. Our emotions range in the extremes and we tend to lose control over them. These acts are often not premeditated because we stop thinking rationally.
Walking away from the situation is a very good start. Lock your self in your room, punch some pillows and scream into them. That usually helps some for me. Too bad there isn't always pillows hanging around in a office

.
When I am stuck some-where without a pillow or a lockable room and I feel that bubbling/boiling feeling kreep up from my stomach, I close my eyes, clench my teeth, fists and every other muscle in my body untill I have drained my self to such an extent that I don't have anything to throw things/words around with. It's still a bit of a disconcerting sight, but rather better than full out reaction to it.
I hear you on the Lithium lullaby

But I like it too much to quit it
Unfortunately, I can't suggest any medications as most medication have totally different affect from one patient to the next. Your best bet is to see your dr regularly so he can asses your reaction to the medication and swap them out untill you get a good balance.
It's been an ongoing struggle for me to find a good balance between "Acceptable" levels of symptoms/side-effects and as the one medication fades out, the search begins all over.
I hope this helped a bit.
Regards