Low fee set by client Hello I am using an old BitCoin client named MultiBit v.0.5.18. There is no option to change a fee. My transactions that I was send two days ago still in 'Unconfirmed status' and I guess here is a problem because I cannot move money from this wallet and may will never can do it.

The wallet set the default fee to 44.843 sat/B. It is lower for current time. I see the middle fee is 220 sat/b for now from https://bitcoinfees.21.co/. 

How can I solve the problem? Is it possible to open wallet through another client? Electrum for example. Or I should wait when fees will go down (if not?).
A transaction with 44.8 sat/B should probably confirm most weekends, the fees had been dropping down to 5-10 in the last weekends. Sometimes even 1 sat/B transactions confirmed. This weekend the mempool seems pretty full, though. 

AFAIK, MultiBit has an option to export private keys. However, MultiBit uses compressed private keys, while Electrum uses uncompressed private keys. Bitcoin Core understands either, so if you don't want to wait for the transaction to confirm, you could install Bitcoin Core to doublespend them. This comes with a wait time though, as you'd have to wait for Bitcoin Core to synchronize with the Bitcoin network which can take a few days. If you're time-pressed, I think Blockchain.info does allow importing keys also, although I would just use it then to send your money to electrum, so that you only relinquish control of your own funds as briefly as possible.