Unfortunately it's not possible to determine which side of the family all your DNA matches are without phasing. In order to phase your matches completely, you need to have either your mother or father, or another close relative, also test – which it sounds like is not possible in your case.
The problem why you cannot identify a certain match as maternal or paternal is because the DNA test does not sequence the chromosomes. Instead, key points in the genome are tested - single nucleotide polymorphisms (SNPs). Essentially, for each SNP, you are going to have two nucleotides (A, C, T, or G). At a given SNP, your result might be CT – the C came from one parent, the T from the other. However there is no way to tell whether the C is from mum or dad. By testing a parent or close relative, you can determine which matches come from which side of the family. For more on phasing see the ISOGG Wiki.
Certainly follow up with your DNA matches to see what relatives they had in your particular locality, but this will obviously be difficult.
I would start with trying to research your mother's family first, because you have something to go on. Even if it's just a name, it's something to go on. Finding her birth record should lead you to her parents. I would speak to local archives to see what records are available (I suspect many containing information on living persons may be restricted access). If you can narrow some of your DNA matches to your mother's side, then that's a start.
I would not get too caught up on the ethnicity estimates; you have to treat the results with a grain of salt. For example, my results from one company say 10% Italian, yet I have traced all my lines of ancestry many generations back (most at least to early 1800s), and yet to find an ancestor born outside of England.
Finally, you did not state which company you tested your DNA with, but if you have not already done so, I would encourage you to transfer your data to all possible sources – Gedmatch, FamilyTreeDNA, MyHeritage. All of these companies accept free transfers – free matches with other cousins. Gedmatch has a number of tools which can be helpful with triangulating matches.
Best of luck in the search, keep in mind that you will get additional DNA matches over time so it may just be a bit of a waiting game until the key match turns up.