Write a time machine quine

CJam, 25

L{\_l~(>1<lN+a@+`@"_~"}_~

Try it online

Explanation:

L      push an empty array (this is the array of previous strings)
{…}    push this block
_      duplicate the block
~      execute the 2nd copy (the stack contains the array and the block)

The block:

\      swap the array with the block
_      duplicate the array
l      read a line from the input (containing the integer n)
~(     evaluate n and decrement it
>      slice the array starting at that position
1<     slice the resulting array to keep only the first string (if any)
l      read the 2nd line from the input (containing the string)
N+     append a newline
a      wrap in an array
@      bring the previous array to the top
+      concatenate the arrays, thus prepending the new string
`      convert the array to its string representation
@      bring the block to the top
"_~"   push this string

At the end, the requested string (if any), the array's representation, the block and the string "_~" are printed automatically.

Python, 221 bytes

import sys
o,p=[''],r'import sys;a,o,p=int(sys.argv[2]),[{2},{0}],{1};print o[a] if len(o)>a else "","\n",p.format(`sys.argv[1]`,`p`,",".join(`s`for s in o))'
print '\n',p.format(`sys.argv[1]`,`p`,','.join(`s`for s in o))

To test this easily, use ./thisgolf.py "yourfirststring" | python -c "import sys;exec(sys.stdin.read().split('\n')[1])" "your second string" <N>, repeating the last bit as many times as you'd like.

Python 2, 207 bytes

def r(O,R):import sys,marshal as m;a=sys.argv;b=int(a[2]);O.extend(["",""]*b);O[b]=a[1];print"%s\nfrom marshal import*;c=%r;i=lambda:0;i.__code__=loads(c);i(%r,i)"%(O[0],m.dumps(R.__code__),O[1:])
r([""],r)

Built on my other quine but changes program, this task is simpler so I was able to golf this further. If I was able to take the input to stdin, this should be much shorter.