I was really surprised to see the price of new vinyl now (not having bought any for at least 40 odd years). Unless it's something I really want, then I'll stick to the second hand market. I've just bought 3 more LPs from Ebay for around a tenner each, which isn't bad, and is what you'd pay for a CD now...albeit a recent release.That's a good solid set-up, with a very strong cost/enjoyment ratio. My suggestion is to get at least a couple of years out of it before you consider any major changes beyond the repositioning already recommended. An MC would be overkill on that deck, and you'd have to add an external phono stage too.
My best advice is to avoid going further down the hi-fi rabbit warren at this stage. You've done you research and, with the help of a retailer with particular talents for well performing affordable systems, you have a rewarding set-up. Utilise that to enjoy the music - it's far more satisfying.
As for vinyl, it has become very expensive indeed. One of my favourite albums (Once Again, by Barclay James Harvest) has been reissued on quality vinyl, but I can't justify or afford the £47 that is being charged for it.