Anyone know where I can get this or other Vietnamese herbs on the Eastside
I have purchased rau ram at Uwajimaya in Bellevue before (recently, even) but I don't know if it's regularly available there. The Seattle ID location didn't have it consistently back when I used to shop there every week.
There's a Viet Wah in Renton on NE Sunset Blvd (WA 900 east of the 405) that might be your best bet.
If you use it often, you might consider growing it. It grow like crazy in containers. I got some at Swansons nursery 2 years ago and it keeps on going despite being neglected. (may be just a little early in the season to get it though).