The coffee shop that I often go to has high grade coffee
「私がよく行っているコーヒーの店は上質なコーヒーを提供する」は英語で The coffee shop that I often go to has high grade coffee もしくは The cafe that I often go to serves incredibly delicious coffee になると思います。
私がよく行っているコーヒーの店 - The coffee shop/cafe (that) I often go to
上質な- high quality, high grade
コーヒー - coffee
提供する- serve
incredibly delicious - とっても美味しい、格段に/格別に美味しい