here's a technique i'm trying for making my own vias. i snip off part of a component lead (like a capacitor or something) that fits through the hole snugly, then cut it off, leaving ~0.5mm protruding from both sides of the board. then i clamp it tightly in a vise to smoosh it down.
for the antenna connection, i've soldered some very thin coax to the launch. the other end was pre-terminated to an SMA connector. you can often buy these online as U.FL to SMA adapters; just snip off the U.FL connector. (the ferrite beads limit common-mode currents.)