You are not required to make estimated quarterly payments. You only need to make an estimated payment if you want to avoid an underpayment penalty. Based on what you described, there will be little or no penalty. My advice: don't bother with estimated payments.
If the stocks you sold were owned for more than 1 year, the "profit" is considered long term capital gains (LTG). Most (probably all) LTG, for someone with $38K AGI, is taxed at 0%.
The TurboTax (TT) software is easily capable of handling stock sales. You don't need a professional. But, you may have to pay for a software upgrade to TT Premier.
