There is a flower shop across the road from my house.

Evimin karsisindaki yolda bir cicekevi vardir (sorry accents dont work)

In this sentance is the meaning changed if the ki ending is omitted ?

Could someone explain its use in this context.. many thanks.

On a sentence level the function of -ki in this case is to change evimin karşısında from an adverbial of place (modifying the predicate) into an adjective attribute (modifying the following noun).

The exact translation may clear it to you:

                ´There is a flower shop in the road which is opposite to my house.´

Thanks to -ki the head of that structure is yol.