Adding to this:
Not a lawyer etc but I don't think a 401k prevents you from making IRa contributions either. Never heard of that.
As for income limits, you can still contribute to your IRA if your income is above the limit (I think that's 125k or so) but the contributions will no longer be tax deductible.
Once you're past that limit, you may as well convert from regular to Roth IRA (this is called a backdoor conversion) so that your money grows tax free.
