No. I found her on that website by her avatar (which is the same as on the title screen) None of the current Gambit Reward, or other cards that were addad into Nutaku's version of the game during last update has such an avatar. Always check my thread http://harem-battle.club/peropero-se...s-artwork.html first, and then ask such questions if it doesn't answer your question.
As for "how" - sorry, i don't read/speak Japanese, so i can't help you here, and Nutaku often changes such things, so even if someone will translate what it says about the way you can obtain it, form this japanese website, it might be different for Nutaku's version of the game. (for example, Nutaku made this card http://www.outofstandard.jp/peropero...keepThis=true& and this one http://www.outofstandard.jp/peropero...keepThis=true& only tradeable for Medals, while they were R-Gacha Limited cards during the New Year of 2014 and 2015 respectfully in the original DMM.com version of the game, according to the same website/database.)
And they've changed some other cards time of appearance in the game and way of acqiring them in their version of the game, and the girl you are asking about is not currently in Nutaku's verion of PPS - you can check that on our Wiki yourself, looking through the avatars: http://harem-battle.club/wiki/PeroPe...rds?do=listing So it is not really that useful even if someone could translate what it says on the Japanese database page about the way of getting that card.
Also, keep in mind that Gambit Bosses also have nothing in common with those Gambits (for example during Haloween Gambit the bosses were more like "summer-themed" , and during the previous "sports" Gambit all the theree boss girls were, actually, a single person - Riza Shimonozo, who is a doctor, who is also the Golden, 3-Focus Boss during teh current gambit (while there were not a single word about any Clinics, Med-Rooms, doctors or nurses during that or this Gambit)