I like
O'Brien but he's a centre half and we need a specialist right back; some one who can add to our attacks (as well as defend). We've been crying out for someone in this position for several seasons - it has to be our number one priority. This player needs to step straight into the team.
Patterson to be let go
Thereafter, we need another centre forward. I could accept another "prospect" as we need a third option for when injuries inevitably occur later in the season. I feel that Barry could turn into a real player for us so I wouldn't want to hamper his development by bringing in a 30+ year old on big wages.
Next I'd be looking at left back because whilst Miko is decent defending he doesn't give us enough going forward - this is a position where I would want a first choice purchase that steps straight into the team.