You can add peers manually. Just open ~/.bitmark/bitmark.conf (-linux/mac path) and append at the end of file:
addnode=175.100.3.95
addnode=93.107.125.126
addnode=204.68.122.11
addnode=42.232.206.100
addnode=139.162.232.242
More peers can be found in bitmark explorer:
http://btm.cryptocloudhosting.org/networkAt this moment you can't withdraw BTM from Poloniex, withdrawals are suspended for some time on Poloniex, but you can buy BTM on tradesathosi(
https://tradesatoshi.com/Exchange?market=BTM_BTC), for the fraction of Poloniex price.
Also begin of March Bitmark will be added to Cryptopia, so you will be able to trade there as well.