Olivia I've been having a think about your 4 questions and wanted to give some tentative answers now I have thought more....
Part of me feels I can't really help as I don't know much about the bi polar condition and I have never been in your shoes. However, I am mum to a child by birth, dd aged 11; and by adoption, ds aged 5. I can tell you a bit about the adoption process from the side of the adopter.
1: if I give my child up for adoption will the child I already have be looked in to?
I don't know for sure but I would imagine they will want to talk to you about you and your child and they will be interested in what is best for all of you. Social services do not want to disrupt normal happy families, or even slightly dysfunctional ones, they have enough to do with families who are totally falling apart for I am pretty sure there would be no 'danger' from them. I would say our family is a normal one but at times maybe we are slightly dysfunctional with my dd and ds having some meltdowns, kids sometimes late for school, dd refusing to do homework etc etc - so when I speak of 'slightly dysfunctional' I am thinking of me not anyone else!
2: are there many people that want to adopt newborns or is it likely he/she will end up in the care system?
Nowadays many (if not all) adopters have been through a rigours process (in the UK), both of selection and of training and are often people who do desperately want to parent children, a child or another child in additional to birth children. One would find it hard to get through the process if one did not really want to parent a child by adoption and were not well prepared to do it. Such people would often be delighted to have the chance to adopt a newborn, although they would not be adopted straight away and would likely be in short term foster care before being adopted. Sometimes they will be fostered to adopt etc. But there are no guarantees about how long it would take etc.
3: will my child being mixed race (half black half white) impact how fast my child gets adopted?
I really do not know. I doubt it. Many people (like dh and I) were totally open to adopting a child of mixed heritage. In fact we did apply to adopt a child of mixed heritage, or rather we expressed interest in adoption for a specific child but the adoption services were keen to find a family that reflected the child's background so we were not encouraged to go further. We adopted a while child (and we are white) but that is nothing to do with our preferences, and many adopters I have spoken to are very open about ethnicity/heritage, so I would not let this worry you.
4: who can I contact to start or find out more information regarding the process
You can contact your local social services wherever you are living.
Now may I ask a few questions?
Please can I ask if you have accessed any counselling to help you make this decision?
The internet can be helpful in providing information for you, you could Google around and take a look at ....
www.baaf.org.uk/info/pregnant
But I really think talking to someone in real life could help. The earlier you begin talking to anyone the longer time you have to make a considered decision and to access all the help you can.
E.G.
Do you really know you could not cope or could you cope with the right help?
The feelings you have now for your young child you would one day have for your new baby, so you might one day regret giving them up for adoption. How will you deal with that?
Does the baby's father know that you are pregnant and thinking of adoption? I am not saying anything about this, just asking.
In terms of your bi-polar is there any support for bi-polar parents which you could access?
Many other posters may well have more experience and knowledge about all this but I wanted to chip in a few thoughts and say I am thinking of you and wishing you well at this difficult time.