Hold what you've got.
If currnet prices are lower than the price you bought in at, then by all means buy some more for dollar cost averaging... but other than that just hold on and enjoy the day after day of green on the charts.
Yes, now the altcoin prices are going down which it is not a good sign to convert them to the Bitcoins, please hold your altcoins in the market as long as we see some good altcoin movements in the market. Don't lose patience when the market is in a positive trend and wait for your profit.