I have gt 730 2gb vcard. This card is enough to mine ?
You are looking into GPU mining right. For that you have choose bestest graphics cards like radeon 470 or higher end other radeon model cards to start mining. You can mine with the cards but for bitcoin mining you cannot make better amount using these GPU mining. With this cards you can mine ehtereum, zcash, monero, neo and so on.
To mine a bitcoin, you please buy any ASIC miner to start with. Antminer s9 is the best resource to mine a bitcoin.