This is what I would do to improve this liturgical space and on a shoestring budget
Keep in mind only the altar platform as progressives call it, others call it the sanctuary, is being improved not the nave.
1. The window to the left of the ambo could have a nice faux stained glass application with that vinyl stuff that makes clear windows in homes look like stain glass.
2. The ambo is too large for the space and hides the altar if you sit to the far left chairs as you enter the nave. Thus a smaller ambo is needed.
3. The altar needs to be three steps higher, placed against the wall and with six proportionate candlesticks upon it and above the altar the cross on the right with a corpus placed upon it, even a senior are class’s cut out of a corpus from cardboard and nicely painted in an icon style. The altar with a nice andependium on its facade.
4. Nice contemporary Stations of the Cross placed on the walls of the nave.