You're not a skinny person. I don't want to be mean, but you actually look like you're overweight.
Barely an AA after two years sounds pretty unlikely for you, with that body type, at your age. You should look - with the help of your endo, of course - into your HRT regimen, blood levels, etc. I think it's very likely that it's inadequate. Not enough T suppression, not enough E, delivery method not right for you... the reasons can be many. But I think it's likely that something's off in your HRT.
If everything seems in order (and don't just ask your endo whether it's in order - sometimes they have a completely different idea of "in order" than basic logic - ask them to tell you the details of everything) with your blood tests, then perhaps ask about other delivery methods. For some people, pills work best. For others, it's transdermal. For others (even though I'm not a fan of that method because of the spikes it gives) it's injections. Some people don't have much results with this or that anti-androgen. Etc.
You could put that money in an investment/savings account and let it grow by a few percents until you see what a corrected HRT regiment does for you for a year or two, assuming your HRT needs to be changed, and decide afterwards.
And if your breasts could still grow, it's pretty much the worst idea in the world to get a breast augmentation. Things don't tend to grow normally when there's a freaking balloon in the middle of them.
Even assuming that your breasts have reached their maximum development and everything is in order except that you're unlucky, which I doubt is the case, I don't advise a breast augmentation.
-It's not permanent. You need a new surgery every 10(?) years to change the implant, with the annoyance and spending it implies.
-Breasts are easy to fake through various means, from socks in a bra to full-fledged breast forms. Even just clothing can have impressive effects sometimes. Face, however, on top of being one of the top gender cues, isn't so easy to work with or make better with make-up and whatnot. I still have zero breasts - yes, my HRT is wrong for now - yet I mostly pass thanks to my female voice and androgynous face, despite my entirely male name.
Though, I don't want to rub it in, but before considering any cosmetic surgery, I think you should concentrate on your weight. Maybe even invest that money in a private trainer or something. Because having a better weight can have near-miraculous, unexpected effects on any part of your body - only you don't know which and to what extent. It might change your perception of this or that part requiring surgery or not.
