[dilijasi]

Hello Lukasz
let's try to help you out here shall we?
1. Vipnet follows the 180+270 rule, i.e. a top up of 100Kn will give you 180 days of SIM validity (which for you expires today right), followed by 270 days of inactive period (can't call or text, receive text only) after which they shutdown your SIM in case you don't top up. Should that happen (unlike the EU, the top up credit is NOT transferable to another SIM) you will lose your hard earned dough, simple as that. Based on what you said, I think you're safe for nine more months, if I were you I would wait with the top up.
2. I have never tried it with Vipnet but can tell you that for instance I wasn't able to do the same with Italian Vodafone SIM - my credit card (issued in Croatia) was declined when tried to buy the voucher online.
3. What don't you try a stupid method: you live in Poland right, and there the Voda partner should be the Polkomtel. Ask if it's possible to use their top up vouchers for Vipnet (I know that it works with Voda Italy). Try also Ebay.

Cheers,
Davor