You might need to double check but I believe your '97 ES 300 has an A541E transmission, same as my '94 ES 300. If so then the following specs would apply as to capacities.
I have a pdf on the A541E but it exceeds the max. single upload size for this site. If you think it might be of use I could email it to you.
I did a total flush and refill of mine with Mobil 1 synthetic and experienced a noticeable improvement in smoother shifting if that's possible. The transmission shifted very smooth before the trans flush however. Do it yourself and you know its done right. I had heard the myth of "flush it and it fails" but this has just not been the case with my '94 with over 200K on it.
If you're interested in doing it yourself let me know and I'll post the procedure. It's really easy and takes a couple of hours the first time you do it but this time frame can be trimmed once you get the hang of it.
Incidentally, DO NOT OVERFILL! I don't believe it has a vent.
RE: Fluid type: Dexron II or equivalent
Capacity:
Total: 6.75 liters (7.1 US qts, 5.9 Imp qts)
Drain and refill:
3.5 liters (3.7 US qts, 3.1 Imp qts)
Hope this helps.