G-325s are only required for marriage based petitions and I-485 adjustments. Not needed for parent/child petitions. You may or may not need an attorney depending on the circumstances. Each case is different and an initial consultation is recommended.
Pursuant to the Form I-130 instructions, Form G-325A is required if filing for your spouse, but not required if filing for your mother. However, your mother will need to file Form G-325A when your mother subsequently files a Form I-485 application to adjust her status to permanent resident.
The Form I-130 instructions can be found at the attached link.