Blimey - I won't ask how you managed that :)
As long as you didn't burn the tracks, this is fixable - but it won't be super easy.
I'd start by cleaning up the board - get a tin sucker and/or some desoldering braid and get the tin out of the through-holes for the switch, the connection to the main board, and the USB connector.
While you're at it, clean up the tin around D1, and make sure that R28 and R38 are still connected properly (R38 might have keystoned, R28 looks like it's just twisted, but best to be sure).
For the switch, you're looking for a tactile switch, 6x6mm pth package, with a 3.5mm actuator - though that doesn't matter too much as long as you're not going to hit the button cover (the bit you press).
The board-to-board connector is a 7-pin 1mm pitch right angle connector, but you could just as well use some thin (insulated!) wire here.
As long as you didn't toast the microUSB socket, you should be able to solder that right back on (it's a very fine pitch right next to the housing though), otherwise you'll have to find a replacement - and finding an exact match would take more searching - however, as long as it's a hybrid SMD mount with 7mm spacing for the body pins, you should be good to go. (There's 2 holes for guides in the board, but at least on my V3 they do not appear to be used by the component.)
All in all, though, this does require some relatively fine soldering and you may wish to practice on some other boards before trying to tackle this :)