If you are planning make some returns, then you have to invest a lot more than 15k into it.
Considering the difficulty level of litecoin, with 2000KH/s mining power you would be making around $700 first month( Based on current price). To achieve that 2000 KH/s in the most cost effective way is to get 3 radeon 7950s. These things are almost sold out everywhere. It would cost 70K+ combined. On top of it add an Asrock board, a cheap processor , 4gigs of RAM, 1000 Watts PSU, Hard disc if required or else a thumb drive, riser cables, fans, and a frame.
That is a cost only if you are mining Litecoins.
Try some other currency and hold it for few months before deciding on them.
My portfolio currently containsBitcoin
Litecoin
Bytecoin
TekkenCoin
Betcoin
Loads of Ripples
Few Quarkcoins
PPC
Unobtanium
Freicoin
Feathercoin
and probably others lying on a Hard Drive that i will find one day