The only monthly income is $2000/month from my rollover ira. Can credit card garnish my this income in Texas law

No, and yes. TX protects up to $1M of your retirement funds from creditors (except for the IRS). So they can't get at the principal in your IRA if it's under $1M in vlaue. But once cash is sent to you and you put it into your checking account, it is no longer protected, unless you have declared bankruptcy.