Can someone help me with this hack/feature to my forum?

[EvilLS1]

If I'm understanding what you want, thats easy. No hack necessary.

Just create the two new fields in your admin control panel.. Make a note of the field IDs for the two new fields. You can find out what the ID is by clicking "modify" under profile fields in the admin control panel, then hold your mouse over the new fields.. The field ID is displayed at the end of the URL at the bottom of your screen. Then edit your postbit template and add this wherever you want them to appear:
<smallfont>Currently Playing: $post[fieldX] <br>
X-Box Live gamer tag: $post[fieldX]<br></smallfont> (replace the Xs with the field ID)

You can add the fancy tables around them with html.