Can you give me some step by step?
1) Pick her up
2) Put her over your shoulder
3) Pat her on the back
I think what you want to do is:
With the engine cold...
1) Unbolt the coolant reservoir and lift it up a few inches and set it on the Hood
latch. The reservoir is designed to slip right over it.
2) remove the coolant reservoir cap
With the engine running...
3) add 50/50 mix of coolant and distilled water to reservoir
4) pinch and release the tube going from the radiator to the reservoir several times to get any air out of the system
There is also a bleeder valve on the reservoir, so if you just want to make sure there is no air in the system preventing you from filling it all the way up, you don't have to take the cap off. You can just loosen the bleeder valve (with engine running) and pinch the tube to get any air out. Loosen the bleeder valve slowly and carefully, and don't loosen it too much or you could get hot scalding coolant on you.
In your case, you probably don't need to do all that, just top if off and check to make sure the level remains where it should and you aren't overheating.
I would suggest sticking with Toyota coolant, especially if that's what's in there already. The dealer should have it readily available since they use it all the time in the shop. My dealer sold it to me for $14 a gallon, which is only a few bucks more than what you would pay for most long-life coolant, and is supposed to have additional benefits.