How do I say...

How do I say ''I wish I was better at Japanese.''?
If there is no way to say "I wish I was better at Japanese" then how can I say "I wish I could speak better Japanese." Or "I wish my Japanese skills were better."?

"Motto Nihongo ga jouzu datta ra(umakatta ra)"
もっと日本語が上手だったら（上手かったら）

I wish I was better at Japanese.
もっと日本語がうまかったらいいのに....
Motto Nihonngo ga umakattara iinoni.....

I wish I could speak better Japanese.
もっとうまい日本語がしゃべれたらいいのに....
Motto umai Nihongo ga shyaberetara iinoni.....

I wish my Japanese skills were better.
もっと日本語能力があればいいのに.....
Motto Nihongo-Noryoku ga areba iinoni....