Hi mate I am also doing Southampton season 1 currently in march sitting in 7th place 2 points off 5th.
my advice is as follows - you need a good left back I'd suggest de ceglie on loan then you need a decent cb squllachi you can get for a few hundred thousand - on my save him and hoovield at the back are averaging 7.20 or above. Clyne is decent rb, play schneiderlain and cork cm with lallana and Davies rotating, puncheon and Ramirez are quality out wide and Rodriguez and lambert will be great up top - they bang the goals in
As for further signings adryan is cheap and decent for depth. But I'd strongly recommend Wellington nem who is amazing and has a release fee of 3.5 if u can stretch, if not sell who you can and buy him- he is quality. Also for cover around the 1m mark up front I can recommend Kozak from LAzio.
Hope this helps!