Here's what I would suggest, with some tactics noted. This is using the 30pt. buy you wanted, with the point from levelling up going into Strength.
Also, note that at 8th level this character would go from doing 1d8 + 1 damage to 1d10 + 2; you've caught him at a breakpoint. His unarmed attack bonus would similarly go up by 2; one from levelling and one from the STR increase.
The statistics for the potions are not included in the stat block, as they haven't been consumed yet. I used standard NPC wealth for a 7th level character (7,200gp) for his equipment.
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Test Case the Monk
Medium-Size Male Human Monk 7
Hit Dice: 7d8 + 14 (45 hp)
Initiative: +3 (+3 Dex)
Speed: 50 ft.
AC: 20 (+3 Dex, +3 Wis, +1 Mnk, +2 Armor, +1 Natural Armor)
Attacks: +7/+2 monk; or +8 Shuriken.
Damage: 1d8 + 1 fist; or 1 Shuriken.
Face/Reach: 5ft. by 5ft./5ft.
Special Attacks: Stunning Fist, Improved Trip
Special Qualities: Evasion, Still Mind, Purity of Body, Wholeness of Body, Leap of the Clouds
Saves: Fort +7, Ref +8, Will +8
Str 13, Dex 16, Con 14, Int 10, Wis 16, Cha 8
Skills: Balance +13, Hide +10, Jump +12, Listen +9, Move Silently +10, Tumble +13.
Feats: [Deflect arrows], Dodge, [Improved trip], [Improved Unarmed Strike], Mobility, Spring Attack, [Stunning fist], Weapon Focus: Unarmed Strike.
Equipment: Bracers of Armor +2, Amulet of Natural Armor +1, Potion of Endurance, Potion of Cat’s Grace, Potion of Bull’s Strength, Potion of Cure Moderate Wounds.
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Tactics: Hit and Run. Use Trip attacks with Improved Trip where possible, bouncing away again using Spring Attack if at all possible. Use greater mobility and Balance to lead the fight someplace with broken floors, rubble, whatever, that will limit PC movement and force balance checks.
Between Wholeness of Body (14 HP) and the Potion of Cure Moderate Wounds (2d8 +3), the monk has access to some nice healing. Using potions to enhance ability scores should be a first priority – either by hearing the party approach or by hiding and using the potions after the start of the fight.
If he hears the party (or wins initiative) I would play a waiting game, stalking the party and hitting them – especially any weaker looking types – alone if possible. Good examples would be if the mage hangs back or if the rogue scouts ahead. Above all else: do not let yourself be flanked. Tumble and use the movement rate to avoid the possibility. Using double-moves and (if necessary) running, a character in heavy armor will never catch you.