There are some promising altco that can yield more bitcoin. Find the right altcoin because there are tons of them out there.
It is also possible to track them from the exchange site itself. Have an opinion about the best exchange sites, bittrex and poloniex have been good to me so far
A long-term investment has more potential for growth, Ethereum seems to be doing so well.
What I think is that bitcoins are a better investment than altcoins. Just keep this in mind that buy low sell high. During the fall in prices of bitcoins last week a lot people have bought bitcoins from those who got panic and sold all of their bitcoins. Now they are making a lot profit from the bitcoins as its price is rising.