Hey Laila, welcome to the forums and sorry for the late reply.
Hope it all went well with Capital One and you got approved. Sometimes providing extra documentation can delay your approval, 2 weeks stil sounds reasonable, but I would give them a call again just to make sure they received your documents.
Yes, it’s better to have more than one card on your file. So you are on the right track thinking about a 2nd secured card, specially one that graduates and can grow with you (BOA, Citi, Credit Union, etc.). Some people recommend waiting some months before applying for another card, but if you think you’ll be approved I would go for it. That way you’ll have two cards growing together and the inquiries will fall from your report at the same time in about two years,
Just don’t go crazy applying for cards, you can also get denied for having too many inquiries on your file. Capital One is a good card for rebuilding, but unfortunately it will not grow with you. I’ve had mine for about two years and I’m getting ready to close it in a few months. It has served it’s purpose. I have a BOA secured card that is supposed to graduate next month, so I’m looking forward to that.
Keep us posted!