Have you tried this Bitcoin and Polcoin exchange:
https://www.easycoin.pl/

There is not too much liquidity on PLC market yet, but the exchange is also very young and, probably, hardly anyone knows about it.
...And, after all, it is always better for the coin to have two exchanges than just only one. 
 

... and it may be worth mentioning that the only working POLCOIN exchange is on Cryptopia currently (https://www.cryptopia.co.nz/Exchange/?market=PLC_BTC).

I found on a mining pool forum in Polish (http://forum.polmine.pl/index.php?topic=4204.1530) that there are new web profiles of Polcoin 2.0 (Facebook, Twitter and Google plus):

https://www.facebook.com/polcoin
https://twitter.com/Polcoin
https://plus.google.com/u/0/b/103962837776398663054/103962837776398663054

(so far, there are only Polish versions of these profiles available)

... and of course You may wait for the new client and then create a new address using the portfolio GUI, instead of doing all these command-line things .
The rest of the procedure will be the same:
[1] provide your old address from the old blockchain on the web page http://exchange.polcoin.one.pl,
[2] then enter the sum corresponding to this address from the old chain,
[3] and finally enter the address from the new blockchain that You have just generated in the new client.

Since the http://exchange.polcoin.one.pl is (was when I visited it for the last time) only in Polish, beneath there is a translation of fields You will need to enter Your data in:

[1] "Podaj adres PLC ze starego lancucha" = "Enter your PLC address from the old blockchain"

[2] "Podaj kwotę PLC ze starego lancucha" = "Enter your PLC balance from the old blockchain" (refers only to the balance associated with this particular address, not the whole portfolio)

[3] "Podaj adres PLC z nowego lancucha" = "Enter your PLC address from the new blockchain"


And:

"Przepisz kod z obrazka" = "Enter the captcha code from the image"
"Obrazek nieczytelny? kliknij aby przeladowac" = "Captcha difficult to read? Click here to get another image"


I hope that the developers will prepare English version too.

As far as I know, the opportunity of exchanging old PLC units into new ones will be available for us for some time. So there should be no problem for us to leap with our Polcoins from the old to the new chain also after the new one is launched.