I need help combining these two queries

SELECT
    CASE
    	WHEN C1 LIKE '% %' 
            THEN LEFT(c1, CHARINDEX(' ', c1) -1)
    		ELSE c1
	END,
	CASE
		WHEN c1 LIKE '% %' 
            THEN RIGHT(c1, CHARINDEX(' ', REVERSE(c1)) -1)
	END
FROM
    Table1

SELECT
    c1, c2, c3, c4,
    c5, c6, c7
FROM 
    Table1 
JOIN 
    Table2 ON c3 = t2c2                          
WHERE 
    c4 = 'A' AND c5 = ' ' AND

Both of these queries work fine individually but I need the c1 column have that split the first query produces. I am just unsure how to add the function to the second query.

I's assuming the 2 C1 references in the first block of code is a typo and it should have a different CASE but amend as you see fit:

SELECT CASE
       WHEN C1 LIKE '% %' 
       THEN LEFT(C1, Charindex(' ', C1) -1)
       ELSE C1
       END C1,
       CASE
       WHEN C1 LIKE '% %'
       THEN RIGHT(C1, Charindex(' ', reverse(C1)) -1)
       END C1,
C2, C3, C4, C5, C6, C7
FROM Table1 
JOIN Table2 ON C3 = T2C2                          
WHERE C4 = 'A' 
AND C5 = ' ' 
AND ???

If you prefer to not clutter up your final select list with complex expressions, you can use a CROSS APPLY to calculate these values as intermediate results.

SELECT
    A.c1Left
    ,A.c1Right
    ,c2
    ,c3
    ,c4
    ,c5
    ,c6
    ,c7
FROM Table1 T1
JOIN Table2 T2
    ON c3 = t2c2
CROSS APPLY (
    SELECT
        CASE WHEN T1.c1 LIKE '% %'
            THEN LEFT(T1.c1, CHARINDEX(' ', T1.c1) -1)
            ELSE T1.c1
            END AS C1Left,
        CASE WHEN T1.c1 LIKE '% %'
            THEN RIGHT(T1.c1, CHARINDEX(' ', REVERSE(T1.c1)) -1)
            END AS c1Right
) A
WHERE c4 = 'A' AND c5 = ' ' AND ...

A CROSS APPLY is like a join to a subselect, where that subselect can reference earlier parts of the FROM/JOIN sequence. The results can then be used on later join conditions, where clauses, and the select list (as above). You can even have multiple cross-applies that each build upon the results of one another.

As a side note, it is good practice to alias all of your table references and then use the aliases to explicitly qualify all references back to those tables. Also, I recommend picking and sticking to a consistent capitalization and indentation style. Those who try to later read your code will thank you. Having a mix is very distracting.