。
I've got four aces in my hand.
Literal
I [of-の] place [to-に] ace [subject-が] 4 [counter-枚] coming-is.
A card-game sentence. 僕の所に ('at my place') refers to the hand/space in front of the speaker. エース is katakana for 'ace.' 枚 is the counter for flat objects — cards, paper, sheets. 来ている ('is coming / has come') is ~ている on the momentary 来る ('come'), indicating the resulting state — 'is here, has arrived.'