Cmon, you need ASIC to compete in Crypto world. GPU is like power hungry and low hashrate.
ASIC mining is not compatible with the x11 and x13 algorithms. Go ahed and point your ASIC miner to the darkcoin pool and see what happens.
You can only use a GPU or CPU to mine x11 and x13. When mining x11 and x13 coins, the mining speed is a lot slower than mining bitcoins.
Some people are already mining x11 and x13 with FPGA (based on darkcoin forum). So I am sure ASIC would be here when darkcoin market rise to as huge as litecoin.