Greendot cards will be rejected by internet gambling sites. The card you want to get is the Visa "All Access" Gift Card backed by Netspend.
I could not find this card at my local wallgreens, CVS, or right aid. I bought my all-access card at a VONS/Safeway and desposited onto pokerstars about 3 days ago.
https://www.allaccessgift.com/
The card didn't come in a yellow package for me, and the card looks like the card on the left. I'm located in Southern California if it makes a difference. Just use the store locator on that website and you should be fine.